function over_lay()
{
var browser=navigator.appName;
var b_version=navigator.appVersion;
var version=parseFloat(b_version);
if ((browser=="Microsoft Internet Explorer")
&& (version>=4))
{
	document.getElementById('back').style.width = document.body.clientWidth + "px";
	document.getElementById('back').style.height = document.body.clientHeight + "px";
	document.getElementById('back').style.display = 'block';
	window.location.href = "#";
	
}
else
{
	document.getElementById('back').style.width = document.body.clientWidth + "px";
	document.getElementById('back').style.height =  150 + window.innerHeight + "px";
	document.getElementById('back').style.display = 'block';
	window.location.href = "#";
	
}
}