$(document).ready(function() {	
	
	//Put in the DIV id you want to display
	launchWindow('#modal_dialog');
	
	//if close button is clicked
	$('.modal_window .close').click(function () {
		$('#modal_mask').hide();
		$('.modal_window').hide();
	});		
	
	//if mask is clicked
	/*$('#modal_mask').click(function () {
		$(this).hide();
		$('.modal_window').hide();
	});*/			
	
});

function launchWindow(id) {
	
		//Get the screen height and width
		var maskHeight = $(document).height();
		var maskWidth = $(window).width();
	
		//Set heigth and width to mask to fill up the whole screen
		$('#modal_mask').css({'width':maskWidth,'height':maskHeight});
		
		//transition effect		
		$('#modal_mask').fadeIn(0);	
		$('#modal_mask').fadeTo("fast",0.7);
	
		//Get the window height and width
		var winH = $(window).height();
		var winW = $(window).width();
              
		//Set the popup window to center
		$(id).css('top',  winH/2-$(id).height()/2);
		$(id).css('left', winW/2-$(id).width()/2);
	
		//transition effect
		$(id).fadeIn(0);
	

}