<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
<script language="javascript">
function readid(obj)
{
alert(obj.parentNode.id)
}
</script>
</head><body><div id="123">
<a href="baidu.com" onclick="javascript:readid(this)">click</a>
</div></body>
</html>
alert(obj.parentNode.id);
}