Checking out the JavaScript drawing program example called Doodle at the webreference.com section on JavaScript Programming, I found this bit of CSS that does syntax highlighting: SyntaxHighlighter.css [http://www.webreference.com/css/SyntaxHighlighter.css]
See also the Doodle Javascript programming example provided by WebReference for use of these style classes. Nice bit of work.
Here is a trivial example of the HTML to use of some of SyntaxHighlighter.css classes [from the example article, page 3]:
<div style="width: 700px;"> <textarea name="code" class="javascript" cols="60" rows="10"> <P class=code><script src="core.js" type=text/javascript></script><BR><script src="graphics.js" type=text/javascript></script><BR><script src="canvas.js" type=text/javascript></script><BR><script type=text/javascript><BR>var canvas = null;<BR>function initCanvas() {<BR> canvas = new Canvas($('theCanvas'));<BR>}<BR>window.setTimeout(initCanvas, 10);<BR></script><BR> <div id="theFrame" class="CanvasFrame"></div><BR> <div id="theCanvas" class="Canvas"></div><BR></div></P> </textarea> </div>
Other examples occur in the article.
This CSS seems to make a nice complement to the PHP syntax highlighter blogged about elsewhere.