var setCenterWin= function(elem,w,h) {
			var win=document.getSize(); 
			var scrl=document.getScroll();
			var scrlwin=document.getScrollSize();
			$('darkbg').setStyles({
					display: '',
					overflow: 'hidden',
					top: '0px',
					left: '0px',
					width: scrlwin.x+'px',
					height: scrlwin.y+'px', 
					opacity: '0'
					});
			$('darkbg').morph({
				opacity: '0.5'
			});	
			elem.setStyles({
				overflow: 'hidden',
				display: '',
				top: win.y/2-(h/2)+scrl.y+'px',
				left: win.x/2-(w/2)+scrl.x+'px',
				width: w+'px',
				height:  h+'px'
			});				
};
var morphCenterWin= function(elem,w,h) {
			var win=document.getSize(); 
			var scrl=document.getScroll(); 
			elem.morph({
				top: win.y/2-(h/2)+scrl.y+'px',
				left: win.x/2-(w/2)+scrl.x+'px',
				width: w+'px',
				height:  h+'px'
			});		
};