<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap Example</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<script>
$(document).ready(function(){
$("#link1").click(function(){
$( "div.MainTitle" ).replaceWith( "newTitle" );
});
});
</script>
</head>
<body>
<br>
<div class="container">
<div class="panel-group">
<div class="panel panel-default">
<div class="panel-heading" >
<h4 class="panel-title">
<a data-toggle="collapse" href="#collapse1"><div class="MainTitle">wwCollapsible panel</div></a>
</h4>
</div>
<div id="collapse1" class="panel-collapse collapse">
<div class="panel-body" ID="link1" ><a href="" >Panel Body</a></div>
<div class="panel-body"><a href="">Panel Body</a></div>
<div class="panel-body"><a href="">Panel Body</a></div>
<div class="panel-footer">Panel Footer</div>
</div>
</div>
</div>