<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Example</title>
<script type="text/javascript" src="http://code.jquery.com/jquery-1.8.2.min.js"></script>
<style type="text/css">
.hover{background:#888888;}
</style>
</head>
<body>
<a href="">ссылка</a>
<script type="text/javascript">
$('a').hover(function() {
$(this).addClass('hover');
},function() {
$(this).removeClass('hover');
});
</script>
</body>
</html>