完整代码:
<!DOCTYPE html>
<html>
<head>
<style type="text/css">
.highlight
{
background-color: yellow;
}
.gray
{
background-color: Gray;
}
</style>
<script src="http://code.jquery.com/jquery-1.5.js"></script>
</head>
<body>
<ul>
<li>Look:</li>
<li>This is some text in a paragraph.</li>
<li>This is a note about it.</li>
</ul>
<script type="text/javascript">
$("ul li").first().addClass('highlight');
jQuery("ul li").first().next().addClass('gray');
</script>
</body>
</html>