<html>
<head>
<script type="text/javascript" src="js/jquery-1.3.2.js"></script>
<style type="text/css">
.changeP { font-weight: bold; color:red;}
</style>
<script type="text/javascript">
$(document).ready(function(){
$("input.buttonA").click(function(){ $("p.fifthparagraph").addClass("changeP"); });
$("input.buttonB").click(function(){ $("p.fifthparagraph").removeClass("changeP"); });
});
</script>
</head>
<body>
<input type="button" value="Change" class="buttonA" />
<input type="button" value="Change" class="buttonB" />
<div style="background:#eee;" class="contentToChange">
<h2>Header 2</h2>
<p class="firstparagraph">Lorem ipsum <em>dolor</em> sit amet, consectetuer <em>adipiscing</em> elit, sed diam nonummy nibh euismod <em>tincidunt</em> ut laoreet dolore magna aliquam erat <strong>volutpat</strong>. Ut wisi enim ad minim <em>veniam</em>, quis nostrud exerci <strong>tation</strong> ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.</p>
<p class="fifthparagraph">Lorem ipsum <em>dolor</em> sit amet, consectetuer <em>adipiscing</em> elit, sed diam nonummy nibh euismod <em>tincidunt</em> ut laoreet dolore magna aliquam erat <strong>volutpat</strong>. Ut wisi enim ad minim <em>veniam</em>, quis nostrud exerci <strong>tation</strong> ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.</p>
</div>
</body>
</html>