<HTML>
<HEAD>
<SCRIPT LANGUAGE="JavaScript">
function aa(){
contain.style.visibility=contain.style.visibility=="hidden"?"visible":"hidden";
}
</SCRIPT>
</HEAD>
<BODY>
<button onclick=aa()>test</button>
<div id="contain">
<iframe id="iframe1" name="iframe1" src="
http://www.51js.com" style="width:400px;height:200px"></iframe>
</div>
</BODY>
</HTML>