<html>
<head>
<script type="text/javascript">
function changeLink()
{
document.getElementById('venus').hash="bottom"
}
</script>
</head>
<body>
<img src="/img/eg_planets.jpg"
usemap="#planetmap" />
<map name="planetmap">
<area
id="venus"
shape="circle"
coords="180,139,14"
href ="/example/hdom/venus2.html#top"
alt="Venus" />
</map>
<input type="button" onclick="changeLink()" value="改变链接" />
</body>
</html>