$(document).ready(function() {

	//select all the a tag with name equal to modal
	$('.modal').click(function(e) {

		//Cancel the link behavior
		e.preventDefault();

		//Get the A tag
		var id = $(this).attr('href');

		//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
		$('#mask').css({'width':maskWidth,'height':maskHeight});
   		$('#mask').css("opacity",0);

		//transition effect
		$('#mask').show();
		$('#mask').fadeTo("fast",0.5);

		//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(2000);
         $(id).show();

	});

	//if close button is clicked
	$('.window .close').click(function (e) {
		//Cancel the link behavior
		e.preventDefault();

		$('#mask').hide();
		$('.window').hide();
	});

	//if mask is clicked
	$('#mask').click(function () {
		$(this).hide();
		$('.window').hide();
	});

});