<html>
<head>
<script src="https://libs.baidu.com/jquery/1.10.2/jquery.min.js">
</script>
<script>
$(document).ready(function(){
var x=0;
$("p").click(function(event){
$("p").animate({fontSize:"+=5px"});
x++;
if (x>=2)
{
$(this).unbind(event);
}
});
});
</script>
</head>
<body>
<p style="font-size:20px;">Click this p element to increase its size. The size can only be increased 2 times.</p>
</body>
</html>