function launchWindow(id) {
	
		//Get the screen height and width
		var maskHeight = jQuery(document).height();
		var maskWidth = jQuery(window).width();
	
		//Set heigth and width to mask to fill up the whole screen
		jQuery('#mask').css({'width':maskWidth,'height':maskHeight});
		
		//transition effect		
		jQuery('#mask').fadeIn(1000);	
		jQuery('#mask').fadeTo("slow",0.8);	
	
		//Get the window height and width
		var winH = jQuery(window).height();
		var winW = jQuery(window).width();
              
		//Set the popup window to center
		jQuery(id).css('top',  winH/2-jQuery(id).height());
		jQuery(id).css('left', winW/2-jQuery(id).width()/2);
	
		//transition effect
		jQuery(id).fadeIn(2000); 
		document.body.style.overflow = 'hidden';
}

function closemodal(){
		jQuery('#mask').hide();
		jQuery('.window').hide();
		document.body.style.overflow = 'auto';
}