<div id=main>
<div id=main_tool><a href='###' onclick='s();'>-></a></div>
<div id="main_menu">
<div style="background-color:#ccc;text-align:right;width:100%;hieght:15px;border-bottom:1px solid #000"><A HREF='###' ONCLICK='c();'>X</A></div>
</div>
<div><iframe frameborder=0 id=main_content src='http://126.com'></iframe></div>
</div>
<style>
#main{height:495px;border:1px solid #479924;bottom:0px;}
#main_tool{width:30px;height:100%;background-color:#aeee5a;float:left;}
#main_menu{width:180px;height:100%;float:left;background-color:#eff;border-left:1px solid #000;border-right:1px solid #000;}
#main_content{width:100%;height:100%;border:0px solid #ccc;}
</style>

<script>
function c(){
document.getElementById("main_menu").style.display="none";
}
function s(){
document.getElementById('main_menu').style.display="block";
}
</script>