how do I create a jQuery Popup window on Modx?

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="[(modx_charset)]">
<title>Modal Windows</title>
<base href="[(site_url)]"></base>

<style type="text/css">

/* Z-index of #mask must lower than #boxes .window */
#mask {
  position:absolute;
  z-index:9000;
  background-color:#000;
  display:none;
}
  
#boxes .window {
  position:absolute;
  width:440px;
  height:200px;
  display:none;
  z-index:9999;
  padding:20px;
}


/* Customize your modal window here, you can add background image too */
#boxes #dialog {
  width:375px; 
  height:203px;
}
</style>

<script type="text/javascript" src="http://code.jquery.com/jquery-latest.pack.js"></script>
</head>
<body>
[*content*]
</body>
</head>

<!-- #dialog is the id of a DIV defined in the code below -->
<a href="#dialog" name="modal">Simple Modal Window</a>

<div id="boxes">

	
	<!-- #customize your modal window here -->

	<div id="dialog" class="window">
		<b>Testing of Modal Window</b> | 
		
		<!-- close button is defined as close class -->
		<a href="#" class="close">Close it</a>

	</div>

	
	<!-- Do not remove div#mask, because you'll need it to fill the whole screen -->	
 	<div id="mask"></div>
</div>

<script type="text/javascript">

$(document).ready(function() {	

	//select all the a tag with name equal to modal
	$('a[name=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 height and width to mask to fill up the whole screen
		$('#mask').css({'width':maskWidth,'height':maskHeight});
		
		//transition effect		
		$('#mask').fadeIn(1000);	
		$('#mask').fadeTo("slow",0.8);	
	
		//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); 
	
	});
	
	//if close button is clicked
	$('.window .close').click(function (e) {
		//Cancel the link behavior
		e.preventDefault();
		$('#mask, .window').hide();
	});		
	
	//if mask is clicked
	$('#mask').click(function () {
		$(this).hide();
		$('.window').hide();
	});			
	
});

</script>