function doPos()
{
	var l=document.getElementById("mainLayer");
	var iWidth=window.innerWidth;
	var iHeight=window.innerHeight;
	
	var x=parseInt((iWidth/2)-(parseInt(l.style.width)/2));
	var y=parseInt((iHeight/2)-(parseInt(l.style.height)/2));;
	
	if ( (y/2)!=parseInt(y/2) ) y++;
	if ( (x/2)!=parseInt(x/2) ) x++;
	
	l.style.left=x;
	l.style.top=y;
	
}