<style type="text/css">
*{ margin:0px auto; padding:0px}
#wai{ 100%; height:500px;}
#left{height:500px; background-color:#63C; float:left}
#right{ height:500px; background-color:#FC3; float:left}
#anniu{ 50px; height:50px; background-color:#F30; position:absolute; top:225px; z-index:10; }
#anniu:hover{ cursor:pointer}
</style>
</head>
<body>
<div id="wai">
<div id="left" style="200px"></div>
<div id="right" style="800px"></div>
</div>
<div id="anniu" style="left:175px" onclick="hua()"></div>
<script type="text/javascript">
var id;
function hua()
{
id = window.setInterval("dong()",10);
}
//滑动的方法，调一次滑动3px
function dong()
{
//改蓝色的宽度 200px
var zuo = document.getElementById("left");
kd = zuo.style.width;
if(parseInt(kd.substr(0,kd.length-2))>=800)
{
window.clearInterval(id);
return;
}
kd = parseInt(kd.substr(0,kd.length-2))+3;
zuo.style.width = kd+"px";
//改黄色的宽度
var you = document.getElementById("right");
ykd = you.style.width;
ykd = parseInt(ykd.substr(0,ykd.length-2))-3;
you.style.width = ykd+"px";
//改红色的left
var hong = document.getElementById("anniu");
hleft = hong.style.left;
hleft = parseInt(hleft.substr(0,hleft.length-2))+3;
hong.style.left = hleft+"px";
}
</script>