<svg xmlns="http://www.w3.org/2000/svg">
  <text xml:lang="en" x="50%" y="10%" text-anchor="middle" fill="blue">
    Click the circle below.  If the color of the circle has changed to green,
    then your browser passes this test.
  </text>
  <style type="text/css">
    circle {
      fill: blue;
    }
  </style>
  <circle cx="50%" cy="50%" r="20%" onclick="
    var o = document.getElementsByTagNameNS ('http://www.w3.org/2000/svg', 'style')[0];
    var n = document.createElementNS ('http://www.w3.org/2000/svg', 'style');
    n.type = 'text/css';
    n.textContent = 'circle { fill: green }';
    o.parentNode.replaceChild (n, o);
  "/>
</svg>
