Jeff's code works fine for me... Your missing a closing "}" for the function...
<script type="text/javascript">
function highlight(el) {
el.style.backgroundColor =
el.style.backgroundColor == "yellow" ?
"" : "yellow";
}
</script>
Programming today is a race between software engineers striving to build better and bigger idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning. - Rick Cook (No, I'm not Rick)