function screenWidth() {
	
	var leftval= screen.width;
	
	document.getElementById('floatimage').style.left=((screen.width/2)-490)+'px';
	document.getElementById('floatheader').style.left=((screen.width/2)-490)+'px';
	document.getElementById('floatdocument').style.left=((screen.width/2)-490)+'px';
	document.getElementById('floatdocument').style.width=980+'px';
	document.getElementById('floatheader').style.width=980+'px';
	alert(((screen.width/2)-490));
}