function centerElement(el) {
		var viewSize = window.getSize();
		var fullSize = window.getScrollSize();
		var elementSize = el.getSize();
		var top = 0;
		
		if (viewSize.y > elementSize.y){	
			var top = (viewSize.y / 2) - (elementSize.y / 2);
		}
	
		el.setStyle('margin-top', top+'px');
	}

window.addEvents({

	'domready': function(){

		if ($chk($('wrapper'))) {
			centerElement($('wrapper'));
		}

	},
	'resize': function(){

		if ($chk($('wrapper'))) {
			centerElement($('wrapper'));
		}

	}

}); // end domready function