Here is an example of what ZippyV is talking about (with a twist)... copy and paste the code below into a new file with an HTML extension and run it!
<html>
<head>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js" type="text/javascript"></script>
</head>
<body>
<h1>This is the title</h1>
<p>This is a paragraph</p>
<div id="hidden-content"></div>
<p>Another paragraph</p>
<input type="button" id="add-content" value="Add Hidden Content" />
<script type="text/javascript">
$(document).ready(function() {
$("#add-content").click(
function() {
var info = unescape('%53%68%68%68%2E%2E%2E%20%73%65%63%72%65%74%20%69%6E%66%6F%72%6D%61%74%69%6F%6E');
$("#hidden-content").html(info);
}
);
});
</script>
</body>
</html>
The twist is that the hidden content to be displayed is first escaped (using the Javascript escape() function). Also, you can place the javascript in a separate file!