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.