<html>
<head>
<script>
function getload()
{
var all=document.body.offsetWidth;
var final=all-1000;
document.getElementById('test').style.width=final+"px";
}
</script>
</head>
<body onload="getload()">
<div id="test" style="border:1px solid blue;">hello
</div>
</dody>
</html>
here get the document body width it provide the current document width by browser resolution.
