function show_popup(el)
{
	var windowWidth = document.documentElement.clientWidth;  
	var windowHeight = document.documentElement.clientHeight;  
	var popupHeight = $(el).height();  
	var popupWidth = $(el).width();  
	  
	$(el).css({  
		"top": windowHeight / 2 - popupHeight / 2,  
		"left": windowWidth / 2 - popupWidth / 2  
	}).fadeIn('slow');  
	
	
}