2004/id/draft-ietf-html-i18n-01.txt


Network Working Group                                       F. Yergeau
Internet Draft                                                G. Nicol
<draft-ietf-html-i18n-01.txt>                                 G. Adams
Expires 30 March 1996                                        M. Duerst
                                                     25 September 1995


         Internationalization of the Hypertext Markup Language


Status of this Memo

   This document is an Internet-Draft.  Internet-Drafts are working doc-
   uments of the Internet Engineering Task Force (IETF), its areas, and
   its working groups. Note that other groups may also distribute work-
   ing documents as Internet-Drafts.

   Internet-Drafts are draft documents valid for a maximum of six
   months. Internet-Drafts may be updated, replaced, or obsoleted by
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   Drafts as reference material or to cite them other than as a "working
   draft" or "work in progress".

   To learn the current status of any Internet-Draft, please check the
   1id-abstracts.txt listing contained in the Internet-Drafts Shadow
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   (Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific
   Rim).

   Distribution of this document is unlimited.  Please send comments to
   the HTML working group (HTML-WG) of the Internet Engineering Task
   Force (IETF) at <html-wg@oclc.org>. Discussions of the group are
   archived at URL: http://www.acl.lanl.gov/HTML_WG/archives.html.


Abstract

   The Hypertext Markup Language (HTML) is a simple markup language used
   to create hypertext documents that are platform independent.  Ini-
   tially, the application of HTML on the World Wide Web was seriously
   restricted by its reliance on the ISO-8859-1 coded character set,
   which is appropriate only for Western European languages.  Despite
   this restriction, HTML has been widely used with other languages,
   using other coded character sets or character encodings, through var-
   ious ad hoc extensions to the language.

   This document is meant to address the issue of the internationaliza-
   tion of HTML by extending the specification of HTML 2.0 and giving


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   additional recommendations for proper internationalisation support.
   A foremost consideration is to make sure that HTML remains a valid
   application of SGML, while enabling its use in all languages of the
   world.

   The "text/html; version=2.1" Internet Media Type [RFC1590] and MIME
   Content Type [RFC1521] is defined by this specification, taken
   together with the HTML 2.0 specification [HTML-2].


Table of contents

   1.  Introduction .................................................. 2
     1.1. Scope ...................................................... 3
     1.2. Conformance ................................................ 3
   2. The document character set ..................................... 5
     2.1. Reference processing model ................................. 5
     2.2. The HTML 2.1 document character set ........................ 7
     2.3. Undisplayable characters ................................... 8
   3. Language tags .................................................. 8
   4. Additional entities, attributes and elements ...................10
     4.1. Full Latin-1 entity set ....................................10
     4.2. Markup for language-dependent presentation .................10
   5. Forms ..........................................................12
     5.1. DTD additions ..............................................12
     5.2. Form submission ............................................13
   6. Miscellaneous ..................................................14
   7. HTML public text ...............................................15
     7.1. HTML DTD ...................................................15
     7.2. SGML declaration for HTML ..................................30
     7.3. Entity sets ................................................31
       7.3.1. ISO Latin 1 character entity set .......................31
   Bibliography ......................................................34
   Authors' Addresses ................................................36


1.  Introduction

   The Hypertext Markup Language (HTML) is a simple markup language used
   to create hypertext documents that are platform independent.  Ini-
   tially, the application of HTML on the World Wide Web was seriously
   restricted by its reliance on the ISO-8859-1 coded character set,
   which is appropriate only for Western European languages.  Despite
   this restriction, HTML has been widely used with other languages,
   using other coded character sets or character encodings, through var-
   ious ad hoc extensions to the language [TAKADA].

   This document is meant to address the issue of the


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   internationalization of HTML by extending the specification of HTML
   2.0 and giving additional recommendations for proper internationali-
   sation support.  It is in good part based on a paper by one of the
   authors on multilingualism on the WWW [NICOL].  A foremost considera-
   tion is to make sure that HTML remains a valid application of SGML,
   while enabling its use in all languages of the world.

   The specific issues addressed are the SGML document character set to
   be used for HTML, the proper treatment of the charset parameter asso-
   ciated with the "text/html" content type and the specification of
   language tags and additional entities.


1.1 Scope

   HTML has been in use by the World-Wide Web (WWW) global information
   initiative since 1990.  This specification extends the capabilities
   of HTML 2.0 (RFC xxx), primarily by removing the restriction to the
   ISO-8859-1 coded character set [ISO-8859-1].  Together with the HTML
   2.0 specification, it defines a new version of HTML to be known as
   "HTML 2.1".

   HTML is an application of ISO Standard 8879:1986, Information Pro-
   cessing Text and Office Systems -- Standard Generalized Markup Lan-
   guage (SGML) [ISO-8879]. The HTML Document Type Definition (DTD) is a
   formal definition of the HTML syntax in terms of SGML.  This specifi-
   cation amends the DTD of HTML 2.0 in order to make it applicable to
   documents encompassing a character repertoire much larger than that
   of ISO-8859-1, while still remaining SGML conformant.

   Together with the HTML 2.0, specification, this specification also
   defines HTML as an Internet Media Type [RFC1590] and MIME Content
   Type [RFC1521] called "text/html", or "text/html; version=2.1". As
   such, it defines the semantics of the HTML syntax and how that syntax
   should be interpreted by user agents.


1.2 Conformance

   This specification governs the syntax of HTML documents and aspects
   of the behavior of HTML user agents.

1.2.1 Documents

   A document is a conforming HTML document if:

   *  It is a conforming SGML document, and it conforms to the HTML DTD
      (see 7.1, "HTML DTD").


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   *  It conforms to the application conventions in this specification.
      For example, the value of the HREF attribute of the <A> element
      must conform to the URI syntax.

1.2.2. User agents

   An HTML user agent conforms to this specification if:

   *  It parses the characters of an HTML document into data characters
      and markup according to SGML [ISO-8879].

        NOTE -- In the interest of robustness and extensibility,
        there are a number of widely deployed conventions for han-
        dling non-conforming documents.  See section 4.2.1 of the
        HTML 2.0 specification [HTML-2], "Undeclared Markup Error
        Handling" for details.

   *  It supports at least the ISO-8859-1 character encoding scheme and
      processes each character in the ISO Latin Alphabet No. 1 as speci-
      fied in section 6.1 of [HTML-2].

      To ensure interoperability and proper support for at least
      ISO-8859-1 in an environment where character encoding schemes
      other than ISO-8859-1 are present, user agents must correctly
      interpret the charset parameter accompanying an HTML document
      received from the network.

      Furthermore, conforming user-agents are required to at least parse
      correctly numeric character references within the range of the
      Basic Multilingual Plane (BMP) of ISO 10646-1 [ISO-10646].

        NOTE -- To support non-western writing systems, HTML user
        agents are encouraged to support `UNICODE-1-1' or similar
        character encoding schemes and as much of the character
        repertoire of [ISO-10646] as is practical.

   *  It behaves identically for documents whose parsed token sequences
      are identical.

      For example, comments and the whitespace in tags disappear during
      tokenization, and hence they do not influence the behavior of con-
      forming user agents.

   *  It allows the user to traverse (or at least attempt to traverse,
      resources permitting) all hyperlinks from <A> elements in an HTML
      document.

   An HTML user agent is a level 2 user agent if, additionally:


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   *  It allows the user to express all form field values specified in
      an HTML document and to (attempt to) submit the values as requests
      to information services.

2. The document character set

2.1. Reference processing model

   This overview explains the reference processing model used for HTML
   2.1, and in particular the SGML concept of a document character set.
   An actual implementation may widely differ in its internal workings
   from the model given below, but should behave as described to an out-
   side observer.

   Because there are various widely differing encodings of text, SGML
   does not directly address the question of how characters are encoded
   e.g. in a file. SGML views the characters as a single set (called a
   "character repertoire"), and a "code set" that assigns an integer
   number (known as "character number") to each character in the reper-
   toire.  The document character set declaration defines what each of
   the character numbers represents [GOLD90, p. 451].  In most cases, an
   SGML DTD and all documents that refer to it have a single document
   character set, and all markup and data characters are part of this
   set.

   HTML, as an application of SGML, does not directly address the ques-
   tion of how characters are encoded as octets in external representa-
   tions such as files. This is deferred to mechanisms external to HTML,
   such as the HTTP protocol, or MIME for electronic mail.

   For the HTTP protocol [HTTP], the way characters are encoded is
   defined by the "charset" parameter[1] of the "Content-Type" field of
   the header of an HTTP response. For example, to indicate that the
   transmitted document is encoded in the "JIS" encoding of Japanese
   [RFC1468], the header will contain the following line:

   Content-Type: text/html; charset=ISO-2022-JP

_________________________
  [1] The term "charset" in MIME is used to designate a
character encoding, rather than a coded  character  set
as  the  term  may  suggest.  A character encoding is a
mapping (possibly many-to-one) of a sequence of  octets
to  a  sequence  of  characters  taken from one or more
character repertoires.  A coded character set is a map-
ping  between  individual  bit  patterns and individual
characters from a single character repertoire.


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   The default charset parameter in case of the HTTP protocol is
   ISO-8859-1 (the so-called "Latin-1" for Western European characters).
   The HTTP protocol also defines a mechanism for the client to specify
   the character encodings it can accept. Clients and servers are
   strongly requested to use these mechanisms to assure correct trans-
   mission and interpretation of any document. Provisions that can be
   taken to help correct interpretation, even in cases where a server or
   client do not yet use these mechanisms, are described in section 6.

   Similarly, if HTML documents are transferred by electronic mail, the
   character encoding is defined by the "charset" parameter of the "Con-
   tent-Type" MIME header line [RFC1521].

   In the case any other way of transferring and storing HTML documents
   are defined or become popular, it is advised that similar provisions
   should be made to clearly identify the character encoding used and/or
   to use a single/default encoding capable of representing the widest
   range of characters used in an international context.

   Whatever the external character encoding actually be, the reference
   processing model translates it to a representation of the document
   character set specified in Section 2.2 before processing specific to
   SGML/HTML.  The reference processing model can be depicted as fol-
   lows:

     [resource]->[decoder]->[entity ]->[ SGML ]->[application]->[display]
                            [manager]  [parser]
                                ^          |
                                |          |
                                +----------+

   The decoder is responsible for decoding the external representation
   of the resource to a representation using the document character set.
   The entity manager, the parser, and the application deal only with
   characters of the document character set.  A display-oriented part of
   the application or the display machinery itself may again convert
   characters represented in the document character set to some other
   representation more suitable for their purpose. In any case, the
   entity manager, the parser, and the application, as far as character
   semantics are concerned, are using the HTML 2.1 document character
   set only.

   An actual implementation may choose, or not, to translate the docu-
   ment into some encoding of the document character set as described
   above; the behaviour described by this reference processing model can
   be achieved otherwise.  This subject is well out of the scope of this
   specification, however, and the reader is invited to consult the SGML
   standard [ISO-8879] or a SGML handbook [BRYAN88] [GOLD90] [VANH90]


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   [SQ91] for further information.

   The most important consequence of this reference processing model is
   that numeric character references are always resolved to the same
   characters, whatever the external encoding actually used. For an
   example, see Section 2.2.

2.2. The HTML 2.1 document character set

   The document character set, in the SGML sense, of HTML 2.1 is the
   Basic Multilingual Plane of ISO 10646:1993 [ISO-10646], also known as
   UCS-2.  This is code-by-code identical with the Unicode standard
   [UNICODE].  The adoption of this document character set implies a
   change in the SGML declaration specified in the HTML 2.0 specifica-
   tion (section 9.5 of [HTML-2]).  The change amounts to removing the
   two BASESET specifications and their accompanying DESCSET declara-
   tions, replacing them with the following declaration:

     BASESET "ISO Registration Number 176//CHARSET
              ISO/IEC 10646-1:1993 UCS-2 with implementation level 3
              //ESC 2/5 2/15 4/5"
     DESCSET  0   9     UNUSED
              9   2     9
              11  2     UNUSED
              13  1     13
              14  18    UNUSED
              32  95    32
              127 1     UNUSED
              128 32    UNUSED
              160 65374 160

   Making UCS-2 the document character set does not create non-
   conformance of any expression, construct or document that is conform-
   ing to HTML 2.0.  It does make conforming certain constructs that are
   not admissible in HTML 2.0.  One consequence is that data characters
   outside the repertoire of ISO-8859-1, but within that of UCS-2 become
   valid SGML characters.  Another is that the upper limit of the range
   of numeric character references is extended from 255 to 65533[2] ;
   thus, &#1048; is a valid reference to a "CYRILLIC CAPITAL LETTER I".
   [ERCS] is a good source of information on Unicode and SGML, although
   its scope and technical content differ greatly from this
_________________________
  [2] 65533  (FFFD hexadecimal) is the last valid char-
acter in UCS-2. 65534 (FFFE hexadecimal) is  unassigned
and  reserved as the byte-swapped version of ZERO WIDTH
NON-BREAKING SPACE  for  byte-sex  detection  purposes.
65535 (FFFF hexadecimal) is unassigned.


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   specification.

   ISO 10646-1:1993 is the most encompassing character set currently
   existing, and there is no other character set that could take its
   place as the document character set for HTML 2.1. Also, it is
   expected that with future extensions of ISO 10646, this specification
   may also be extended.  If nevertheless for a specific application
   there is a need to use characters outside this standard, this should
   be done by avoiding any conflicts with present or future versions of
   ISO 10646, i.e. by assigning these characters to a private zone.
   Also, it should be borne in mind that such a use will be highly
   unportable; in many cases, it may be better to use inline bitmaps.

2.3. Undisplayable characters

   With the document character set being the full ISO 10646 BMP, the
   possibility that a character cannot be displayed due to lack of
   appropriate resources (fonts) cannot be avoided. Because there are
   many different things that can be done in such a case, this document
   does not recommend any specific behaviour. Depending on the implemen-
   tation, this may also be handled by the underlaying display system
   and not the application itself.  The following considerations, how-
   ever, may be of help:

   -  A clearly visible, but unobtrusive behaviour should be preferred.
      Some documents may contain many characters that cannot be renden-
      dered, and so showing an alert for each of them is not the right
      thing to do.

   -  In case a numeric representation of the missing character is
      given, its hexadecimal (not decimal) form is to be preferred,
      because this form is used in character set standards [ERCS].

3. Language tags

   Language tags can be used to control rendering of a marked up docu-
   ment in various ways: character disambiguation, in cases where the
   character encoding is not sufficient to resolve to a specific glyph;
   quotation marks; hyphenation; ligatures; spacing; voice synthesis;
   etc.  Independently of rendering issues, language markup is useful as
   content markup for purposes such as classification and searching.

   The language attribute, LANG, takes as its value a language tag that
   identifies a natural language spoken, written, or otherwise conveyed
   by human beings for communication of information to other human
   beings. Computer languages are explicitly excluded.

   The syntax and registry of HTML language tags is the same as that


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   defined by RFC 1766 [RFC1766]. In summary, a language tag is composed
   of one or more parts: A primary language tag and a possibly empty
   series of subtags:

        language-tag  = primary-tag *( "-" subtag )
        primary-tag   = 1*8ALPHA
        subtag        = 1*8ALPHA

   Whitespace is not allowed within the tag and all tags are case-
   insensitive. The namespace of language tags is administered by the
   IANA. Example tags include:

       en, en-US, en-cockney, i-cherokee, x-pig-latin

   Two-letter primary-tags are reserved for ISO 639 language abbrevia-
   tions [ISO-639], and three-letter primary-tags for the language
   abbreviations of the "Ethnologue" [ETHNO] (the latter is in addition
   to the requirements of RFC 1766). Any two-letter initial subtag is an
   ISO 3166 country code [ISO-3166].

   In the context of HTML, a language tag is not to be interpreted as a
   single token, as per RFC 1766, but as a hierarchy. For example, a
   user agent that adjusts rendering according to language should con-
   sider that it has a match when a language tag in a style sheet entry
   matches the initial portion of the language tag of an element. An
   exact match should be preferred. This interpretation allows an ele-
   ment marked up as, for instance, "en-US" to trigger styles corre-
   sponding to, in order of preference, US-English ("en-US") or 'plain'
   or 'international' English ("en").

        NOTE -- using the language tag as a hierarchy does not
        imply that all languages with a common prefix will be
        understood by those fluent in one or more of those lan-
        guages; it simply allows the user to request this commonal-
        ity when it is true for that user.

   Since any text can logically be assigned a language, almost all HTML
   elements admit the LANG attribute.  The DTD reflects this.  It is
   also intended that any new element introduced in later versions of
   HTML will admit the LANG attribute, unless there is a good reason not
   to do so.

   The rendering of elements is meant to be controlled (in part) by the
   LANG attribute.  Specific user preferences set within the browser
   should override the value of the LANG attribute, which in turn over-
   rides the value specified by the LANG attribute of any enclosing ele-
   ment. If none of these are set, a suitable default, perhaps con-
   trolled by the user's locale, should be used to control rendering.


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4. Additional entities, attributes and elements

4.1. Full Latin-1 entity set

   According to the suggestion of section 14 of [HTML-2], the set of
   Latin-1 entities is extended to cover the whole right part of
   ISO-8859-1.  The names of the entities are taken from the appendices
   of [SGML].  A list is provided in section 7.3.1 of this specifica-
   tion.

4.2. Markup for language-dependent presentation

   For the correct presentation of text from certain languages (irre-
   spective of formatting issues), some support in the form of addi-
   tional entities and elements is needed.  In particular, bidirectional
   text (BIDI for short) requires markup in special circumstances where
   ambiguities as to the directionnality of some characters have to be
   resolved.  Plain text may contain this markup in the form of special-
   purpose characters; in HTML, these are replaced by SGML markup to be
   described below.

   This markup affects the ability to render BIDI text in a semantically
   legible fashion.  That is, without this special BIDI markup, cases
   arise which would prevent *any* rendering whatsoever that reflected
   the basic meaning of the text. It is for this reason that these spe-
   cial characters were added to Unicode (and, thence, to ISO/IEC
   10646).  If it were possible to do reliable layout and rendering of
   bidirectionnal text without them, they definitely would not have been
   included in Unicode.

   First, a set of named character entities is added that allows partial
   support of the Unicode bidirectional algorithm [UNICODE], plus some
   help with languages requiring contextual analysis for rendering:

   <!ENTITY zwnj CDATA "&#8204;"--=zero width non-joiner-->
   <!ENTITY zwj  CDATA "&#8205;"--=zero width joiner-->
   <!ENTITY lrm  CDATA "&#8206;"--=left-to-right mark-->
   <!ENTITY rlm  CDATA "&#8207;"--=right-to-left mark-->

   The first two, zwnj and zwj, are used to force or block joining
   behavior in contexts which joining would occur but should not or
   would not occur but should.  For example, ARABIC LETTER HEH is used
   to abbreviate "Hijri" (the Islamic calendrical system); however, the
   isolated form of HEH looks like the digit five as employed in Arabic
   script (actually based on Indic digits).  In order to prevent one
   from reading HEH as a final digit five in a year, the initial form of
   HEH is used.  However, there is no following context (i.e., a joining
   letter) to which the HEH can join.  Therefore, the ZWJ is used to


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   provide that context.  In Farsi texts, there are cases where a letter
   that normally would join a subsequent letter in a cursive connection
   does not.  Here the ZWNJ is used.

   The other two, lrm and rlm, are used to disambiguate directionality
   of directionally neutral characters, e.g., if you have a double quote
   sitting between an Arabic and a Latin letter, then which direction
   does the quote resolve to?  These characters are like zero width
   spaces which have a directional property (but no word/line break
   property).

   Next, an attribute called DIR is introduced, restricted to the values
   LTR and RTL and admitted by most elements.  On block-type elements,
   the DIR attribute indicates the base directionnality of the text in
   the block; if omitted it is inherited from the parent element.  On
   inline elements, it makes the element start a new embedding level; if
   omitted the inline element does not start a new embedding level.
   Embedding is used to handle nested directional runs; a common need
   for the embedding characters is to handle text that has been pasted
   from one bidi context to another, and the possibility of multiply
   embedded pastings.  Following is an example of a case where embedding
   is needed, showing its effect:

        Given the following latin (upper case) and arabic (lower
        case) letters in backing store with the specified embed-
        dings (LRE is shorthand for <SPAN DIR=LTR>, RLE for <SPAN
        DIR=RTL> and PDF for </SPAN>):

        LRE A B RLE a b LRE C D PDF c d PDF E F PDF

        One gets the following rendering (with [] showing the
        directional transitions):

        [ A B [ d c [ C D ] b a ] E F ]

        On the other hand, without these characters, e.g., with

        A B a b C D c d E F

        and a base level of LTR one gets the following rendering:

        [ A B [ b a ] C D [ d c ] E F ]

        Notice that b,a is on the left and d,c on the right unlike
        the above case where the embedding levels are used.  With-
        out the embedding characters one has at most two levels: a
        base directional level and a single counterflow directional
        level.


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        A directionnal override feature is needed to deal with
        unusual pieces of text in which directionality cannot be
        resolved from context in an unambiguous fashion. For exam-
        ple, in part numbers, formulas, telephone numbers, and
        other similar pieces of text, it is difficult or impossible
        to derive the directionality of numbers, punctuation, and
        other neutrals from their context.  To this effect, a new
        element called BDO (BIDI override) is introduced, which
        requires the DIR attribute to specify whether the override
        is left-to-right or right-to-left.

        A few other additional elements are important to have for
        proper language-dependent rendering.  First, a generic con-
        tainer is needed to carry the LANG and BIDI attributes in
        cases where no other element is appropriate; the SPAN ele-
        ment is introduced for that purpose.

        Short quotations, and in particular the quotation marks
        surrounding them, are typically rendered differently in
        different languages and on platforms with different graphic
        capabilities: "a quotation in English", `another, slightly
        better one', ,,a quotation in German", << a quotation in
        French >>.  The <Q> element is introduced for that purpose.

        Many languages, including English, require superscripts for
        proper rendering: "the XXth century" should have "th" in
        superscript.  The <SUP> element, and its sibling <SUB>, are
        introduced to allow proper markup of such text.  <SUP> and
        <SUB> contents are restricted to PCDATA to avoid nesting
        problems.

        Finally, in many languages text justification is much more
        important than it is in Western languages, and justifies
        markup.  The ALIGN attribute, admitting values of LEFT,
        RIGHT, CENTER and JUSTIFY, is added to a selection of ele-
        ments where it makes sense (block-like).

5. Forms


5.1. DTD additions

   It is natural to expect input in any language in forms, as they pro-
   vide one of the only ways of obtaining user input. While this is pri-
   marily a UI issue, there are some things that should be specified at
   the HTML level to guide behavior and promote interoperability.

   To ensure interoperability, it is necessary for the user agent (and


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   the user) to have an indication of the character set(s) that the
   server providing a form will be able to handle upon submission of the
   filled-in form.  Such an indication is provided by the ACCEPT-CHARSET
   attribute of the FORM element, modeled on the HTTP Accept-Charset
   header (see [HTTP]), which contains a space and/or comma delimited
   list of character sets acceptable to the server.  A user agent may
   want to somehow advise the user of the contents of this attribute, or
   to restrict his possibility to enter unacceptable characters.

        NOTE -- The list of character sets is to be interpreted as
        an EXCLUSIVE-OR list; the server announces that it is ready
        to accept any ONE of these character encoding schemes for
        each part of a multipart entity.


5.2. Form submission

   The HTML 2.0 form submission mechanism, based on the "application/x-
   www-form-urlencoded" media type, is hopelessly broken with regard to
   internationalization.  In fact, since URLs are restricted to ASCII
   characters, the mechanism is broken even for ISO-8859-1 text.  Sec-
   tion 2.2 of [RFC1738] specifies that octets may be encoded using the
   "%HH" notation, but text submitted from a form is composed of charac-
   ters, not octets.  Lacking a specification of a character encoding
   scheme, the "%HH" notation has no meaning.

   A partial solution to this sorry state of affairs is to specify a
   default character encoding scheme to be assumed when the GET method
   of form submission is used.  Specifying UCS-2 would break all exist-
   ing forms, so the only sensible way is to designate ISO-8859-1.  That
   is, the encoded URL sent to submit a form by the GET method is to be
   interpreted as a sequence of single-octet characters encoded accord-
   ing to ISO-8859-1, and further encoded according to the scheme of
   [RFC1738] (the "%HH" notation).  This is clearly insufficient, so the
   GET method of form submission is deprecated and should not be used in
   future documents, despite the language of section XX of [HTML-2].

   A better solution is to add a MIME charset parameter to the Content-
   Type header sent along with a POST method form submission, with the
   understanding that the URL encoding of [RFC1738] is applied on top of
   the specified character encoding, as a kind of implicit Content-
   Transfer-Encoding.  The default ISO-8859-1 is to be implied in the
   absence of a charset parameter.

   The best solution is to use the "multipart/form-data" media type
   described in [FILE-UPLOAD] with the POST method of form submission.
   This mechanism encapsulates the value part of each name-value pair in
   a body-part of a multipart MIME body that is sent as the HTTP entity;


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   each body part can be labeled with an appropriate Content-Type,
   including if necessary a charset parameter that specifies the charac-
   ter encoding scheme.  The changes to the DTD necessary to support
   this method of form submission have been incorporated in the DTD
   included in this specification.

   How the user agent determines the encoding of the text entered by the
   user is outside the scope of this specification.

6. Miscellaneous

   Proper interpretation of a text document requires that the character
   encoding scheme be known.  Current HTTP servers, however, do not gen-
   erally include an appropriate charset parameter with the Content-Type
   header, even when the encoding scheme is different from the default
   ISO-8859-1.  This is bad behaviour, and as such strongly discouraged,
   but some preventive measures can be taken to minimize the detrimental
   effects.

   In the case where a document is accessed from a hyperlink in an ori-
   gin HTML document, a CHARSET attribute is added to the attribute list
   of elements with link semantics (A and LINK), specifically by adding
   it to the linkExtraAttributes entity.  The value of that attribute is
   to be considered a hint to the User Agent as to the character encod-
   ing scheme used by the ressource pointed to by the hyperlink; it
   should be the appropriate value of the MIME charset parameter for
   that ressource.

   In any document, it may be wise to include an indication of the
   encoding scheme like the following, as early as possible within the
   HEAD of the document:

    <META HTTP-EQUIV="Content-Type"
     CONTENT="text/html; charset=ISO-2022-JP">

   This is not foolproof, but will work if the encoding scheme is such
   that ASCII characters stand for themselves at least until the META
   element is parsed.

   For definiteness, the "charset" parameter received from the source of
   the document should be considered the most authoritative, followed in
   order of preference by the contents of a META element such as the
   above, and finally the CHARSET parameter of the anchor that was fol-
   lowed (if any).

   When HTML text is transmitted directly in UCS-2
   (charset=UNICODE-1-1), the question of byte order arises: does the
   high-order byte of each two-byte character come first or second?  For


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   definiteness, this specification recommends that UCS-2 be transmitted
   in big-endian byte order (high order byte first), which corresponds
   both to the established network byte order for two-byte quantities
   and to the Unicode recommendation for serialized text data.  Further-
   more, to maximize chances of proper interpretation, it is recommended
   that documents transmitted as UCS-2 always begin with a ZERO-WIDTH
   NON-BREAKING SPACE character (hexadecimal FEFF) which, when byte-
   reversed becomes number FFFE, a character guaranteed to be never
   assigned.  Thus, a user-agent receiving an FFFE as the first octets
   of a text would know that bytes have to be reversed for the remainder
   of the text.

7. HTML Public Text

7.1. HTML DTD

   <!--    html-2.1.dtd

           Document Type Definition for the HyperText Markup Language,
           version 2.1 (HTML DTD)

           Last revised: 95/09/25

           Authors: Daniel W. Connolly <connolly@w3.org>
                    Francois Yergeau <yergeau@alis.com>
   -->

   <!ENTITY % HTML.Version
           "-//IETF//DTD HTML 2.1//EN"

           -- Typical usage:

               <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.1//EN">
               <html>
               ...
               </html>
           --
           >


   <!--============ Feature Test Entities ========================-->

   <!ENTITY % HTML.Recommended "IGNORE"
           -- Certain features of the language are necessary for
              compatibility with widespread usage, but they may
              compromise the structural integrity of a document.
              This feature test entity enables a more prescriptive
              document type definition that eliminates


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              those features.
           -->

   <![ %HTML.Recommended [
           <!ENTITY % HTML.Deprecated "IGNORE">
   ]]>

   <!ENTITY % HTML.Deprecated "INCLUDE"
           -- Certain features of the language are necessary for
              compatibility with earlier versions of the specification,
              but they tend to be used and implemented inconsistently,
              and their use is deprecated. This feature test entity
              enables a document type definition that eliminates
              these features.
           -->

   <!ENTITY % HTML.Highlighting "INCLUDE"
           -- Use this feature test entity to validate that a
              document uses no highlighting tags, which may be
              ignored on minimal implementations.
           -->

   <!ENTITY % HTML.Forms "INCLUDE"
           -- Use this feature test entity to validate that a document
              contains no forms, which may not be supported in minimal
              implementations
           -->

   <!--============== Imported Names ==============================-->

   <!ENTITY % Content-Type "CDATA"
           -- meaning an internet media type
              (aka MIME content type, as per RFC1521)
           -->

   <!ENTITY % HTTP-Method "GET | POST"
           -- as per HTTP specification, in progress
           -->

   <!--========= DTD "Macros" =====================-->

   <!ENTITY % heading "H1|H2|H3|H4|H5|H6">

   <!ENTITY % list " UL | OL | DIR | MENU " >

   <!ENTITY % attrs -- common attributes for elements --
            "LANG  NAME      #IMPLIED  -- RFC 1766 language tag --
             DIR  (ltr|rtl) #IMPLIED  -- text directionnality --">


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   <!ENTITY % just -- an attribute for text justification --
            "ALIGN  (left|right|center|justify)  #IMPLIED">

   <!--======= Character mnemonic entities =================-->

   <!ENTITY % ISOlat1 PUBLIC
     "ISO 8879-1986//ENTITIES Added Latin 1//EN//HTML">
   %ISOlat1;

   <!--Entities for markup significant characters -->
   <!ENTITY amp CDATA "&#38;"     -- ampersand          -->
   <!ENTITY gt CDATA "&#62;"      -- greater than       -->
   <!ENTITY lt CDATA "&#60;"      -- less than          -->
   <!ENTITY quot CDATA "&#34;"    -- double quote       -->

   <!--Entities for language-dependent presentation (BIDI and contextual analysis) -->
   <!ENTITY zwnj CDATA "&#8204;"-- zero width non-joiner-->
   <!ENTITY zwj  CDATA "&#8205;"-- zero width joiner-->
   <!ENTITY lrm  CDATA "&#8206;"-- left-to-right mark-->
   <!ENTITY rlm  CDATA "&#8207;"-- right-to-left mark-->

   <!--========= SGML Document Access (SDA) Parameter Entities =====-->

   <!-- HTML 2.0 contains SGML Document Access (SDA) fixed attributes
   in support of easy transformation to the International Committee
   for Accessible Document Design (ICADD) DTD
            "-//EC-USA-CDA/ICADD//DTD ICADD22//EN".
   ICADD applications are designed to support usable access to
   structured information by print-impaired individuals through
   Braille, large print and voice synthesis.  For more information on
   SDA & ICADD:
           - ISO 12083:1993, Annex A.8, Facilities for Braille,
             large print and computer voice
           - ICADD ListServ
             <ICADD%ASUACAD.BITNET@ARIZVM1.ccit.arizona.edu>
           - Usenet news group bit.listserv.easi
           - Recording for the Blind, +1 800 221 4792
   -->

   <!ENTITY % SDAFORM  "SDAFORM  CDATA  #FIXED"
             -- one to one mapping        -->
   <!ENTITY % SDARULE  "SDARULE  CDATA  #FIXED"
             -- context-sensitive mapping -->
   <!ENTITY % SDAPREF  "SDAPREF  CDATA  #FIXED"
             -- generated text prefix     -->
   <!ENTITY % SDASUFF  "SDASUFF  CDATA  #FIXED"
             -- generated text suffix     -->
   <!ENTITY % SDASUSP  "SDASUSP  NAME   #FIXED"


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             -- suspend transform process -->

   <!--========== Text Markup =====================-->

   <![ %HTML.Highlighting [

   <!ENTITY % font " TT | B | I ">

   <!ENTITY % phrase "EM | STRONG | CODE | SAMP | KBD | VAR | CITE">

   <!ENTITY % text "#PCDATA|A|IMG|BR|%phrase|%font|SPAN|Q|BDO|SUP|SUB">

   <!ELEMENT (%font;|%phrase) - - (%text)*>
   <!ATTLIST ( TT | CODE | SAMP | KBD | VAR )
           %attrs;
           %SDAFORM; "Lit"
           >
   <!ATTLIST ( B | STRONG )
           %attrs;
           %SDAFORM; "B"
           >
   <!ATTLIST ( I | EM | CITE )
           %attrs;
           %SDAFORM; "It"
           >

   <!-- <TT>       Typewriter text                         -->
   <!-- <B>        Bold text                               -->
   <!-- <I>        Italic text                             -->
   <!-- <EM>       Emphasized phrase                       -->
   <!-- <STRONG>   Strong emphasis                         -->
   <!-- <CODE>     Source code phrase                      -->
   <!-- <SAMP>     Sample text or characters               -->
   <!-- <KBD>      Keyboard phrase, e.g. user input        -->
   <!-- <VAR>      Variable phrase or substituable         -->
   <!-- <CITE>     Name or title of cited work             -->

   <!ENTITY % pre.content "#PCDATA|A|HR|BR|%font|%phrase|SPAN|BDO">

   ]]>

   <!ENTITY % text "#PCDATA|A|IMG|BR|SPAN|Q|BDO|SUP|SUB">

   <!-- Should the BDO element have an SDAFORM attr.?  Which? -->
   <!ELEMENT BDO - - (%text)+>
   <!ATTLIST BDO
           LANG   NAME      #IMPLIED
           DIR    (ltr|rtl) #REQUIRED


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           >

   <!-- <BDO>     Control bidirectionnal text             -->

   <!ELEMENT BR    - O EMPTY>
   <!ATTLIST BR
           %SDAPREF; "&#RE;"
           >

   <!-- <BR>       Line break      -->

   <!-- Should the SPAN element have an SDAFORM attr.?  Which? -->
   <!ELEMENT SPAN - - (%text)*>
   <!ATTLIST SPAN
           %attrs;
   >

   <!-- <SPAN>     Generic container        -->

   <!ELEMENT Q - - (%text)*>
   <!ATTLIST Q
           %attrs;
           %SDAFORM; "It"  -- to be verified --
           >

   <!-- <Q>        Short quotation                         -->

   <!ELEMENT (SUP|SUB) - - (#PCDATA)>
   <!ATTLIST (SUP|SUB)
           %attrs;
           >

   <!-- <SUP>      Superscript              -->
   <!-- <SUB>      Subscript                -->

   <!--========= Link Markup ======================-->

   <!ENTITY % linkType "NAME">

   <!ENTITY % linkExtraAttributes
           "REL %linkType #IMPLIED
           REV %linkType #IMPLIED
           URN CDATA #IMPLIED
           TITLE CDATA #IMPLIED
           METHODS NAMES #IMPLIED
           CHARSET NAME #IMPLIED
           ">


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   <![ %HTML.Recommended [
           <!ENTITY % A.content   "(%text)*"
           -- <H1><a name="xxx">Heading</a></H1>
                   is preferred to
              <a name="xxx"><H1>Heading</H1></a>
           -->
   ]]>

   <!ENTITY % A.content   "(%heading|%text)*">

   <!ELEMENT A     - - %A.content -(A)>
   <!ATTLIST A
           %attrs;
           HREF CDATA #IMPLIED
           NAME CDATA #IMPLIED
           %linkExtraAttributes;
           %SDAPREF; "<Anchor: #AttList>"
           >
   <!-- <A>                Anchor; source/destination of link      -->
   <!-- <A NAME="...">     Name of this anchor                     -->
   <!-- <A HREF="...">     Address of link destination             -->
   <!-- <A URN="...">      Permanent address of destination        -->
   <!-- <A REL=...>        Relationship to destination             -->
   <!-- <A REV=...>        Relationship of destination to this     -->
   <!-- <A TITLE="...">    Title of destination (advisory)         -->
   <!-- <A METHODS="...">  Operations on destination (advisory)    -->
   <!-- <A CHARSET="...">  Charset of destination (advisory)       -->


   <!--========== Images ==========================-->

   <!ELEMENT IMG    - O EMPTY>
   <!ATTLIST IMG
           %attrs;
           SRC CDATA  #REQUIRED
           ALT CDATA #IMPLIED
           ALIGN (top|middle|bottom) #IMPLIED
           ISMAP (ISMAP) #IMPLIED
           %SDAPREF; "<Fig><?SDATrans Img: #AttList>#AttVal(Alt)</Fig>"
           >

   <!-- <IMG>              Image; icon, glyph or illustration      -->
   <!-- <IMG SRC="...">    Address of image object                 -->
   <!-- <IMG ALT="...">    Textual alternative                     -->
   <!-- <IMG ALIGN=...>    Position relative to text               -->
   <!-- <IMG ISMAP>        Each pixel can be a link                -->

   <!--========== Paragraphs=======================-->


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   <!ELEMENT P     - O (%text)*>
   <!ATTLIST P
           %attrs;
           %just;
           %SDAFORM; "Para"
           >

   <!-- <P>        Paragraph       -->


   <!--========== Headings, Titles, Sections ===============-->

   <!ELEMENT HR    - O EMPTY>
   <!ATTLIST HR
           %attrs;
           %just;
           %SDAPREF; "&#RE;&#RE;"
           >

   <!-- <HR>       Horizontal rule -->

   <!ELEMENT ( %heading )  - -  (%text;)*>
   <!ATTLIST H1
           %attrs;
           %just;
           %SDAFORM; "H1"
           >
   <!ATTLIST H2
           %attrs;
           %just;
           %SDAFORM; "H2"
           >
   <!ATTLIST H3
           %attrs;
           %just;
           %SDAFORM; "H3"
           >
   <!ATTLIST H4
           %attrs;
           %just;
           %SDAFORM; "H4"
           >
   <!ATTLIST H5
           %attrs;
           %just;
           %SDAFORM; "H5"
           >
   <!ATTLIST H6


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           %attrs;
           %just;
           %SDAFORM; "H6"
           >

   <!-- <H1>       Heading, level 1 -->
   <!-- <H2>       Heading, level 2 -->
   <!-- <H3>       Heading, level 3 -->
   <!-- <H4>       Heading, level 4 -->
   <!-- <H5>       Heading, level 5 -->
   <!-- <H6>       Heading, level 6 -->


   <!--========== Text Flows ======================-->

   <![ %HTML.Forms [
           <!ENTITY % block.forms "BLOCKQUOTE | FORM | ISINDEX">
   ]]>

   <!ENTITY % block.forms "BLOCKQUOTE">

   <![ %HTML.Deprecated [
           <!ENTITY % preformatted "PRE | XMP | LISTING">
   ]]>

   <!ENTITY % preformatted "PRE">

   <!ENTITY % block "P | %list | DL
           | %preformatted
           | %block.forms">

   <!ENTITY % flow "(%text|%block)*">

   <!ENTITY % pre.content "#PCDATA | A | HR | BR | SPAN | BDO">
   <!ELEMENT PRE - - (%pre.content)*>
   <!ATTLIST PRE
           %attrs;
           WIDTH NUMBER #implied
           %SDAFORM; "Lit"
           >

   <!-- <PRE>              Preformatted text               -->
   <!-- <PRE WIDTH=...>    Maximum characters per line     -->

   <![ %HTML.Deprecated [

   <!ENTITY % literal "CDATA"
           -- historical, non-conforming parsing mode where


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              the only markup signal is the end tag
              in full
           -->

   <!ELEMENT (XMP|LISTING) - -  %literal>
   <!ATTLIST XMP
           %attrs;
           %SDAFORM; "Lit"
           %SDAPREF; "Example:&#RE;"
           >
   <!ATTLIST LISTING
           %attrs;
           %SDAFORM; "Lit"
           %SDAPREF; "Listing:&#RE;"
           >

   <!-- <XMP>              Example section         -->
   <!-- <LISTING>          Computer listing        -->

   <!ELEMENT PLAINTEXT - O %literal>
   <!-- <PLAINTEXT>        Plain text passage      -->

   <!ATTLIST PLAINTEXT
           %attrs;
           %SDAFORM; "Lit"
           >
   ]]>


   <!--========== Lists ==================-->

   <!ELEMENT DL    - -  (DT | DD)+>
   <!ATTLIST DL
           %attrs;
           COMPACT (COMPACT) #IMPLIED
           %SDAFORM; "List"
           %SDAPREF; "Definition List:"
           >

   <!ELEMENT DT    - O (%text)*>
   <!ATTLIST DT
           %attrs;
           %SDAFORM; "Term"
           >

   <!ELEMENT DD    - O %flow>
   <!ATTLIST DD
           %attrs;


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           %SDAFORM; "LItem"
           >

   <!-- <DL>               Definition list, or glossary    -->
   <!-- <DL COMPACT>       Compact style list              -->
   <!-- <DT>               Term in definition list         -->
   <!-- <DD>               Definition of term              -->

   <!ELEMENT (OL|UL) - -  (LI)+>
   <!ATTLIST OL
           %attrs;
           %just;
           COMPACT (COMPACT) #IMPLIED
           %SDAFORM; "List"
           >
   <!ATTLIST UL
           %attrs;
           %just;
           COMPACT (COMPACT) #IMPLIED
           %SDAFORM; "List"
           >
   <!-- <UL>               Unordered list                  -->
   <!-- <UL COMPACT>       Compact list style              -->
   <!-- <OL>               Ordered, or numbered list       -->
   <!-- <OL COMPACT>       Compact list style              -->


   <!ELEMENT (DIR|MENU) - -  (LI)+ -(%block)>
   <!ATTLIST DIR
           %attrs;
           %just;
           COMPACT (COMPACT) #IMPLIED
           %SDAFORM; "List"
           %SDAPREF; "<LHead>Directory</LHead>"
           >
   <!ATTLIST MENU
           %attrs;
           %just;
           COMPACT (COMPACT) #IMPLIED
           %SDAFORM; "List"
           %SDAPREF; "<LHead>Menu</LHead>"
           >

   <!-- <DIR>              Directory list                  -->
   <!-- <DIR COMPACT>      Compact list style              -->
   <!-- <MENU>             Menu list                       -->
   <!-- <MENU COMPACT>     Compact list style              -->


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   <!ELEMENT LI    - O %flow>
   <!ATTLIST LI
           %attrs;
           %just;
           %SDAFORM; "LItem"
           >

   <!-- <LI>               List item                       -->

   <!--========== Document Body ===================-->

   <![ %HTML.Recommended [
           <!ENTITY % body.content "(%heading|%block|HR|ADDRESS|IMG)*"
           -- <h1>Heading</h1>
              <p>Text ...
                   is preferred to
              <h1>Heading</h1>
              Text ...
           -->
   ]]>

   <!ENTITY % body.content "(%heading | %text | %block |
                                    HR | ADDRESS)*">

   <!ELEMENT BODY O O  %body.content>
   <!ATTLIST BODY
           %attrs;
           >

   <!-- <BODY>     Document body   -->

   <!ELEMENT BLOCKQUOTE - - %body.content>
   <!ATTLIST BLOCKQUOTE
           %attrs;
           %just;
           %SDAFORM; "BQ"
           >

   <!-- <BLOCKQUOTE>       Quoted passage  -->

   <!ELEMENT ADDRESS - - (%text|P)*>
   <!ATTLIST  ADDRESS
           %attrs;
           %just;
           %SDAFORM; "Lit"
           %SDAPREF; "Address:&#RE;"
           >


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   <!-- <ADDRESS>  Address, signature, or byline   -->


   <!--======= Forms ====================-->

   <![ %HTML.Forms [

   <!ELEMENT FORM - - %body.content -(FORM) +(INPUT|SELECT|TEXTAREA)>
   <!ATTLIST FORM
           %attrs;
           ACTION CDATA #IMPLIED
           METHOD (%HTTP-Method) GET
           ENCTYPE %Content-Type; "application/x-www-form-urlencoded"
           ACCEPT-CHARSET CDATA #IMPLIED
           %SDAPREF; "<Para>Form:</Para>"
           %SDASUFF; "<Para>Form End.</Para>"
           >

   <!-- <FORM>                     Fill-out or data-entry form     -->
   <!-- <FORM ACTION="...">        Address for completed form      -->
   <!-- <FORM METHOD=...>          Method of submitting form       -->
   <!-- <FORM ENCTYPE="...">       Representation of form data     -->

   <!ENTITY % InputType "(TEXT | PASSWORD | CHECKBOX |
                           RADIO | SUBMIT | RESET |
                           IMAGE | HIDDEN | FILE )">
   <!ELEMENT INPUT - O EMPTY>
   <!ATTLIST INPUT
           %attrs;
           TYPE %InputType TEXT
           NAME CDATA #IMPLIED
           VALUE CDATA #IMPLIED
           SRC CDATA #IMPLIED
           CHECKED (CHECKED) #IMPLIED
           SIZE CDATA #IMPLIED
           MAXLENGTH NUMBER #IMPLIED
           ALIGN (top|middle|bottom) #IMPLIED
           ACCEPT CDATA #IMPLIED --list of content types --
           %SDAPREF; "Input: "
           >

   <!-- <INPUT>                    Form input datum                -->
   <!-- <INPUT TYPE=...>           Type of input interaction       -->
   <!-- <INPUT NAME=...>           Name of form datum              -->
   <!-- <INPUT VALUE="...">        Default/initial/selected value  -->
   <!-- <INPUT SRC="...">          Address of image                -->
   <!-- <INPUT CHECKED>            Initial state is "on"           -->
   <!-- <INPUT SIZE=...>           Field size hint                 -->


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   <!-- <INPUT MAXLENGTH=...>      Data length maximum             -->
   <!-- <INPUT ALIGN=...>          Image alignment                 -->

   <!ELEMENT SELECT - - (OPTION+) -(INPUT|SELECT|TEXTAREA)>
   <!ATTLIST SELECT
           %attrs;
           NAME CDATA #REQUIRED
           SIZE NUMBER #IMPLIED
           MULTIPLE (MULTIPLE) #IMPLIED
           %SDAFORM; "List"
           %SDAPREF;
           "<LHead>Select #AttVal(Multiple)</LHead>"
           >

   <!-- <SELECT>                   Selection of option(s)          -->
   <!-- <SELECT NAME=...>          Name of form datum              -->
   <!-- <SELECT SIZE=...>          Options displayed at a time     -->
   <!-- <SELECT MULTIPLE>          Multiple selections allowed     -->

   <!ELEMENT OPTION - O (#PCDATA)*>
   <!ATTLIST OPTION
           %attrs;
           SELECTED (SELECTED) #IMPLIED
           VALUE CDATA #IMPLIED
           %SDAFORM; "LItem"
           %SDAPREF;
           "Option: #AttVal(Value) #AttVal(Selected)"
           >

   <!-- <OPTION>                   A selection option              -->
   <!-- <OPTION SELECTED>          Initial state                   -->
   <!-- <OPTION VALUE="...">       Form datum value for this option-->

   <!ELEMENT TEXTAREA - - (#PCDATA)* -(INPUT|SELECT|TEXTAREA)>
   <!ATTLIST TEXTAREA
           %attrs;
           NAME CDATA #REQUIRED
           ROWS NUMBER #REQUIRED
           COLS NUMBER #REQUIRED
           %SDAFORM; "Para"
           %SDAPREF; "Input Text -- #AttVal(Name): "
           >

   <!-- <TEXTAREA>            An area for text input -->
   <!-- <TEXTAREA NAME=...>   Name of form datum     -->
   <!-- <TEXTAREA ROWS=...>   Height of area         -->
   <!-- <TEXTAREA COLS=...>   Width of area          -->


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   ]]>


   <!--======= Document Head ======================-->

   <![ %HTML.Recommended [
           <!ENTITY % head.extra "">
   ]]>
   <!ENTITY % head.extra "& NEXTID?">

   <!ENTITY % head.content "TITLE & ISINDEX? & BASE? %head.extra">

   <!ELEMENT HEAD O O  (%head.content) +(META|LINK)>
   <!ATTLIST HEAD
           %attrs;           >

   <!-- <HEAD>     Document head   -->

   <!ELEMENT TITLE - -  (#PCDATA)* -(META|LINK)>
   <!ATTLIST TITLE
           %attrs;
           %SDAFORM; "Ti"    >

   <!-- <TITLE>    Title of document -->

   <!ELEMENT LINK - O EMPTY>
   <!ATTLIST LINK
           %attrs;
           HREF CDATA #REQUIRED
           %linkExtraAttributes;
           %SDAPREF; "Linked to : #AttVal (TITLE) (URN) (HREF)>"    >

   <!-- <LINK>             Link from this document                 -->
   <!-- <LINK HREF="...">  Address of link destination             -->
   <!-- <LINK URN="...">   Lasting name of destination             -->
   <!-- <LINK REL=...>     Relationship to destination             -->
   <!-- <LINK REV=...>     Relationship of destination to this     -->
   <!-- <LINK TITLE="..."> Title of destination (advisory)         -->
   <!-- <LINK CHARSET="..."> Charset of destination (advisory)     -->
   <!-- <LINK METHODS="..."> Operations allowed (advisory)         -->

   <!ELEMENT ISINDEX - O EMPTY>
   <!ATTLIST ISINDEX
           %attrs;
           %SDAPREF;
      "<Para>[Document is indexed/searchable.]</Para>">

   <!-- <ISINDEX>          Document is a searchable index          -->


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   <!ELEMENT BASE - O EMPTY>
   <!ATTLIST BASE
           HREF CDATA #REQUIRED     >

   <!-- <BASE>             Base context document                   -->
   <!-- <BASE HREF="...">  Address for this document               -->

   <!ELEMENT NEXTID - O EMPTY>
   <!ATTLIST NEXTID
           N CDATA #REQUIRED     >

   <!-- <NEXTID>           Next ID to use for link name            -->
   <!-- <NEXTID N=...>     Next ID to use for link name            -->

   <!ELEMENT META - O EMPTY>
   <!ATTLIST META
           HTTP-EQUIV  NAME    #IMPLIED
           NAME        NAME    #IMPLIED
           CONTENT     CDATA   #REQUIRED
           >

   <!-- <META>                     Generic Meta-information        -->
   <!-- <META HTTP-EQUIV=...>      HTTP response header name       -->
   <!-- <META NAME=...>            Meta-information name           -->
   <!-- <META CONTENT="...">       Associated information          -->

   <!--======= Document Structure =================-->

   <![ %HTML.Deprecated [
           <!ENTITY % html.content "HEAD, BODY, PLAINTEXT?">
   ]]>
   <!ENTITY % html.content "HEAD, BODY">

   <!ELEMENT HTML O O  (%html.content)>
   <!ENTITY % version.attr "VERSION CDATA #FIXED '%HTML.Version;'">

   <!ATTLIST HTML
           %attrs;
           %version.attr;
           %SDAFORM; "Book"
           >

   <!-- <HTML>                     HTML Document   -->


7.2. SGML Declaration for HTML

   <!SGML  "ISO 8879:1986"


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   --
           SGML Declaration for HyperText Markup Language version 2.x
           (HTML 2.x).

   --

   CHARSET
            BASESET  "ISO Registration Number 176//CHARSET
                      ISO/IEC 10646-1:1993 UCS-2 with
                      implementation level 3//ESC 2/5 2/15 4/5"
            DESCSET  0   9     UNUSED
                     9   2     9
                     11  2     UNUSED
                     13  1     13
                     14  18    UNUSED
                     32  95    32
                     127 1     UNUSED
                     128 32    UNUSED
                     160 65376 160


   CAPACITY        SGMLREF
                   TOTALCAP        150000
                   GRPCAP          150000
                   ENTCAP          150000

   SCOPE    DOCUMENT
   SYNTAX
            SHUNCHAR CONTROLS 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
                    17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 127
            BASESET  "ISO 646:1983//CHARSET
                      International Reference Version
                      (IRV)//ESC 2/5 4/0"
            DESCSET  0 128 0

            FUNCTION
                     RE            13
                     RS            10
                     SPACE         32
                     TAB SEPCHAR    9

            NAMING   LCNMSTRT ""
                     UCNMSTRT ""
                     LCNMCHAR ".-"
                     UCNMCHAR ".-"
                     NAMECASE GENERAL YES
                              ENTITY  NO
            DELIM    GENERAL  SGMLREF


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                     SHORTREF SGMLREF
            NAMES    SGMLREF
            QUANTITY SGMLREF
                     ATTSPLEN 2100
                     LITLEN   1024
                     NAMELEN  72    -- somewhat arbitrary; taken from
                                   internet line length conventions --
                     PILEN    1024
                     TAGLVL   100
                     TAGLEN   2100
                     GRPGTCNT 150
                     GRPCNT   64

   FEATURES
     MINIMIZE
       DATATAG  NO
       OMITTAG  YES
       RANK     NO
       SHORTTAG YES
     LINK
       SIMPLE   NO
       IMPLICIT NO
       EXPLICIT NO
     OTHER
       CONCUR   NO
       SUBDOC   NO
       FORMAL   YES
     APPINFO    "SDA"  -- conforming SGML Document Access application
                       --
   >


7.3. Entity sets

7.3.1. ISO Latin 1 Character Entity Set

The following public text lists each of the characters specified in the
Added Latin 1 entity set, along with its name, syntax for use, and
description. This list is derived from ISO Standard 8879:1986//ENTITIES
Added Latin 1//EN. HTML includes the entire entity set, and adds enti-
ties for all missing characters in the right part of ISO-8859-1.

 <!-- (C) International Organization for Standardization 1986
      Permission to copy in any form is granted for use with
      conforming SGML systems and applications as defined in
      ISO 8879, provided this notice is included in all copies.
   -->
 <!-- Character entity set. Typical invocation:


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      <!ENTITY % ISOlat1 PUBLIC
        "ISO 8879-1986//ENTITIES Added Latin 1//EN//HTML">
      %ISOlat1;
   -->
 <!ENTITY nbsp   CDATA "&#160;" -- no-break space -->
 <!ENTITY iexcl  CDATA "&#161;" -- inverted exclamation mark -->
 <!ENTITY cent   CDATA "&#162;" -- cent sign -->
 <!ENTITY pound  CDATA "&#163;" -- pound sterling sign -->
 <!ENTITY curren CDATA "&#164;" -- general currency sign -->
 <!ENTITY yen    CDATA "&#165;" -- yen sign -->
 <!ENTITY brvbar CDATA "&#166;" -- broken (vertical) bar -->
 <!ENTITY sect   CDATA "&#167;" -- section sign -->
 <!ENTITY uml    CDATA "&#168;" -- umlaut (dieresis) -->
 <!ENTITY copy   CDATA "&#169;" -- copyright sign -->
 <!ENTITY ordf   CDATA "&#170;" -- ordinal indicator, feminine -->
 <!ENTITY laquo  CDATA "&#171;" -- angle quotation mark, left -->
 <!ENTITY not    CDATA "&#172;" -- not sign -->
 <!ENTITY shy    CDATA "&#173;" -- soft hyphen -->
 <!ENTITY reg    CDATA "&#174;" -- registered sign -->
 <!ENTITY macr   CDATA "&#175;" -- macron -->
 <!ENTITY deg    CDATA "&#176;" -- degree sign -->
 <!ENTITY plusmn CDATA "&#177;" -- plus-or-minus sign -->
 <!ENTITY sup2   CDATA "&#178;" -- superscript two -->
 <!ENTITY sup3   CDATA "&#179;" -- superscript three -->
 <!ENTITY acute  CDATA "&#180;" -- acute accent -->
 <!ENTITY micro  CDATA "&#181;" -- micro sign -->
 <!ENTITY para   CDATA "&#182;" -- pilcrow (paragraph sign) -->
 <!ENTITY middot CDATA "&#183;" -- middle dot -->
 <!ENTITY cedil  CDATA "&#184;" -- cedilla -->
 <!ENTITY sup1   CDATA "&#185;" -- superscript one -->
 <!ENTITY ordm   CDATA "&#186;" -- ordinal indicator, masculine -->
 <!ENTITY raquo  CDATA "&#187;" -- angle quotation mark, right -->
 <!ENTITY frac14 CDATA "&#188;" -- fraction one-quarter -->
 <!ENTITY frac12 CDATA "&#189;" -- fraction one-half -->
 <!ENTITY frac34 CDATA "&#190;" -- fraction three-quarters -->
 <!ENTITY iquest CDATA "&#191;" -- inverted question mark -->
 <!ENTITY Agrave CDATA "&#192;" -- capital A, grave accent -->
 <!ENTITY Aacute CDATA "&#193;" -- capital A, acute accent -->
 <!ENTITY Acirc  CDATA "&#194;" -- capital A, circumflex accent -->
 <!ENTITY Atilde CDATA "&#195;" -- capital A, tilde -->
 <!ENTITY Auml   CDATA "&#196;" -- capital A, dieresis or umlaut mark -->
 <!ENTITY Aring  CDATA "&#197;" -- capital A, ring -->
 <!ENTITY AElig  CDATA "&#198;" -- capital AE diphthong (ligature) -->
 <!ENTITY Ccedil CDATA "&#199;" -- capital C, cedilla -->
 <!ENTITY Egrave CDATA "&#200;" -- capital E, grave accent -->
 <!ENTITY Eacute CDATA "&#201;" -- capital E, acute accent -->
 <!ENTITY Ecirc  CDATA "&#202;" -- capital E, circumflex accent -->
 <!ENTITY Euml   CDATA "&#203;" -- capital E, dieresis or umlaut mark -->


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 <!ENTITY Igrave CDATA "&#204;" -- capital I, grave accent -->
 <!ENTITY Iacute CDATA "&#205;" -- capital I, acute accent -->
 <!ENTITY Icirc  CDATA "&#206;" -- capital I, circumflex accent -->
 <!ENTITY Iuml   CDATA "&#207;" -- capital I, dieresis or umlaut mark -->
 <!ENTITY ETH    CDATA "&#208;" -- capital Eth, Icelandic -->
 <!ENTITY Ntilde CDATA "&#209;" -- capital N, tilde -->
 <!ENTITY Ograve CDATA "&#210;" -- capital O, grave accent -->
 <!ENTITY Oacute CDATA "&#211;" -- capital O, acute accent -->
 <!ENTITY Ocirc  CDATA "&#212;" -- capital O, circumflex accent -->
 <!ENTITY Otilde CDATA "&#213;" -- capital O, tilde -->
 <!ENTITY Ouml   CDATA "&#214;" -- capital O, dieresis or umlaut mark -->
 <!ENTITY times  CDATA "&#215;" -- multiply sign -->
 <!ENTITY Oslash CDATA "&#216;" -- capital O, slash -->
 <!ENTITY Ugrave CDATA "&#217;" -- capital U, grave accent -->
 <!ENTITY Uacute CDATA "&#218;" -- capital U, acute accent -->
 <!ENTITY Ucirc  CDATA "&#219;" -- capital U, circumflex accent -->
 <!ENTITY Uuml   CDATA "&#220;" -- capital U, dieresis or umlaut mark -->
 <!ENTITY Yacute CDATA "&#221;" -- capital Y, acute accent -->
 <!ENTITY THORN  CDATA "&#222;" -- capital Thorn, Icelandic -->
 <!ENTITY szlig  CDATA "&#223;" -- small sharp s, German (sz ligature) -->
 <!ENTITY agrave CDATA "&#224;" -- small a, grave accent -->
 <!ENTITY aacute CDATA "&#225;" -- small a, acute accent -->
 <!ENTITY acirc  CDATA "&#226;" -- small a, circumflex accent -->
 <!ENTITY atilde CDATA "&#227;" -- small a, tilde -->
 <!ENTITY auml   CDATA "&#228;" -- small a, dieresis or umlaut mark -->
 <!ENTITY aring  CDATA "&#229;" -- small a, ring -->
 <!ENTITY aelig  CDATA "&#230;" -- small ae diphthong (ligature) -->
 <!ENTITY ccedil CDATA "&#231;" -- small c, cedilla -->
 <!ENTITY egrave CDATA "&#232;" -- small e, grave accent -->
 <!ENTITY eacute CDATA "&#233;" -- small e, acute accent -->
 <!ENTITY ecirc  CDATA "&#234;" -- small e, circumflex accent -->
 <!ENTITY euml   CDATA "&#235;" -- small e, dieresis or umlaut mark -->
 <!ENTITY igrave CDATA "&#236;" -- small i, grave accent -->
 <!ENTITY iacute CDATA "&#237;" -- small i, acute accent -->
 <!ENTITY icirc  CDATA "&#238;" -- small i, circumflex accent -->
 <!ENTITY iuml   CDATA "&#239;" -- small i, dieresis or umlaut mark -->
 <!ENTITY eth    CDATA "&#240;" -- small eth, Icelandic -->
 <!ENTITY ntilde CDATA "&#241;" -- small n, tilde -->
 <!ENTITY ograve CDATA "&#242;" -- small o, grave accent -->
 <!ENTITY oacute CDATA "&#243;" -- small o, acute accent -->
 <!ENTITY ocirc  CDATA "&#244;" -- small o, circumflex accent -->
 <!ENTITY otilde CDATA "&#245;" -- small o, tilde -->
 <!ENTITY ouml   CDATA "&#246;" -- small o, dieresis or umlaut mark -->
 <!ENTITY divide CDATA "&#247;" -- divide sign -->
 <!ENTITY oslash CDATA "&#248;" -- small o, slash -->
 <!ENTITY ugrave CDATA "&#249;" -- small u, grave accent -->
 <!ENTITY uacute CDATA "&#250;" -- small u, acute accent -->
 <!ENTITY ucirc  CDATA "&#251;" -- small u, circumflex accent -->


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 <!ENTITY uuml   CDATA "&#252;" -- small u, dieresis or umlaut mark -->
 <!ENTITY yacute CDATA "&#253;" -- small y, acute accent -->
 <!ENTITY thorn  CDATA "&#254;" -- small thorn, Icelandic -->
 <!ENTITY yuml   CDATA "&#255;" -- small y, dieresis or umlaut mark -->


Bibliography

   [BRYAN88]      M. Bryan, "SGML -- An Author's Guide to the Standard
                  Generalized Markup Language", Addison-Wesley, Reading,
                  1988.

   [ERCS]         Extended Reference Concrete Syntax for SGML.
                  <http://www.sgmlopen.org/sgml/docs/ercs/ercs-
                  home.html>

   [ETHNO]        "Ethnologue, Languages of the World", 12th Edition,
                  Barbara F. Grimes editor, Summer Institute of Linguis-
                  tics, Dallas, 1992.

   [FILE-UPLOAD]  E. Nebel and L. Masinter, "Form-based File Upload in
                  HTML", Work in progress (draft-ietf-html-
                  fileupload-03.txt), Xerox Corporation, August 1995.

   [GOLD90]       C. F. Goldfarb, "The SGML Handbook", Y. Rubinsky, Ed.,
                  Oxford University Press, 1990.

   [HTML-2]       T. Berners-Lee and D. Connolly, "Hypertext Markup Lan-
                  guage - 2.0", Work in progress (draft-ietf-html-
                  spec-05.txt), MIT/W3C, August 1995.

   [HTTP]         T. Berners-Lee, R. T. Fielding, and H. Frystyk
                  Nielsen, "Hypertext Transfer Protocol - HTTP/1.0",
                  Work in progress (draft-ietf-http-v10-spec-00.ps),
                  MIT, UC Irvine, CERN, March 1995.

   [ISO-639]      ISO 639:1988. Codes pour la reprsentation des noms de
                  langue.  Technical content in
                  <http://www.sil.org/sgml/iso639a.html>

   [ISO-1000]     ISO 1000:1992.  Units SI et recommandations pour
                  l'emploi de leurs multiples et de certaines autres
                  units.

   [ISO-3166]     ISO 3166:1993. Codes pour la reprsentation des noms
                  de pays.

   [ISO-4217]     ISO 4217:1990. Codes pour la reprsentation des


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                  monnaies et types des fonds.

   [ISO-8601]     ISO 8601:1988.  lments de donnes et formats
                  d'change -- change d'information -- Reprsentation
                  de la date et de l'heure.

   [ISO-8859-1]   ISO 8859-1:1987.  International Standard -- Informa-
                  tion Processing -- 8-bit Single-Byte Coded Graphic
                  Character Sets -- Part 1: Latin Alphabet No. 1.

   [ISO-8879]     ISO 8879:1986. International Standard -- Information
                  Processing -- Text and Office Systems -- Standard Gen-
                  eralized Markup Language (SGML).

   [ISO-10646]    ISO/IEC 10646-1:1993. International Standard -- Infor-
                  mation technology -- Universal Multiple-Octet Coded
                  Character Set (UCS) -- Part 1: Architecture and Basic
                  Multilingual Plane.

   [NICOL]        G.T. Nicol, "The Multilingual World Wide Web", Elec-
                  tronic Book Technologies, 1995,
                  <http://www.ebt.com/docs/multling.html>

   [RFC1468]      J. Murai, M. Crispin and E. van der Poel, "Japanese
                  Character Encoding for Internet Messages", RFC 1468,
                  Keio University, Panda Programming, June 1993.

   [RFC1521]      N. Borenstein and N. Freed, "MIME (Multipurpose Inter-
                  net Mail Extensions) Part One: Mechanisms for Specify-
                  ing and Describing the Format of Internet Message Bod-
                  ies", RFC 1521, Bellcore, Innosoft, September 1993.

   [RFC1590]      J. Postel, "Media Type Registration Procedure", RFC
                  1590, USC/ISI, March 1994.

   [RFC1738]      T. Berners-Lee, L. Masinter, and M. McCahill, "Uniform
                  Resource Locators (URL)", RFC 1738, CERN, Xerox PARC,
                  University of Minnesota, October 1994.

   [RFC1766]      H. Alverstrand, "Tags for the Identification of Lan-
                  guages", RFC 1766, UNINETT, March 1995.

   [SQ91]         SoftQuad, "The SGML Primer", 3rd ed., SoftQuad Inc.,
                  1991.

   [TAKADA]       Toshihiro Takada, "Multilingual Information Exchange
                  through the World-Wide Web", Computer Networks and
                  ISDN Systems, Vol. 27, No. 2, Nov. 1994 , p. 235-241.


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   [TEI]          TEI Guidelines for Electronic Text Encoding and Inter-
                  change.  <http://etext.virgina.edu/TEI.html>

   [UNICODE]      The Unicode Consortium, "The Unicode Standard --
                  Worldwide Character Encoding -- Version 1.0", Addison-
                  Wesley, Volume 1, 1991, Volume 2, 1992.  The BIDI
                  algorithm is in appendix A of volume 1, with correc-
                  tions in appendix D of volume 2.

   [VANH90]       E. van Hervijnen, "Practical SGML", Kluwer Academicq
                  Publishers Group, Norwell and Dordrecht, 1990.

Authors' Addresses

   Franois Yergeau
   Alis Technologies
   3410, rue Griffith
   Montral  QC  H4T 1A7
   Canada

   Tel: +1 (514) 738-9171
   Fax: +1 (514) 342-0318
   EMail: yergeau@alis.ca


   Gavin Thomas Nicol
   Electronic Book Technologies, Japan
   1-29-9 Tsurumaki,
   Setagaya-ku,
   Tokyo
   Japan

   Tel + Fax: +81-3-3706-7351
   EMail: gtn@ebt.com, gtn@twics.co.jp


   Glenn Adams
   Stonehand
   118 Magazine Street
   Cambridge, MA 02139
   U.S.A.

   Tel: +1 (617) 864-5524
   Fax: +1 (617) 864-4965
   EMail: glenn@stonehand.com


   Martin J. Duerst


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   Multimedia-Laboratory
   Departement of Computer Science
   University of Zurich
   Winterthurerstrasse 190
   CH-8057 Zurich
   Switzerland

   Tel: +41 1 257 43 16
   Fax: +41 1 363 00 35
   E-mail: mduerst@ifi.unizh.ch


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