<html>
<head>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs
/jquery/1.4.0/jquery.min.js"></script>
</head>
<script type="text/javascript">
$(document).ready(function(){
$("button").click(function(){
$(".id100").height("200px");
$("#id200").width("200px");
});
});
</script>
</head>
<body>
<div class="id100" >
HELLO</div>
<div id="id200" >
W3SCHOOL</div>
<button type="button">Click me</button>
</body>
</html>