.divGlobal,.DivTop,.DivBottom{
min-width:760px;
width:expression(document.body.clientWidth<760?"760px":"100%")/*最小宽度设置*/
width:100%;}
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<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>
<style type="text/css">
.mleft{
float:left;
width:100px;
background:#FF6633;
}
.mright{
float:right;
width:200px;
background:#FF3399;
}
</style>
</head>
<body onresize="turnwidth()" onload="turnwidth()">
<div class="mleft" id="DLeft">left</div><!--mleft-->
<div class="mright" id="DRight">right</div><!--mright-->
<script language="javascript">
function turnwidth(){
var w1=document.body.scrollWidth
var left=document.getElementById("DLeft");
var wright=document.getElementById("DRight").offsetWidth;
var p=w1-wright;
left.style.width=p;
}
</script>
</body>
</html>