<!DOCTYPE html>
<html>
<head>
<title></title>
<style type="text/css">
.div{
width: 200px;
height: 200px;
background-color: lightgreen;
}
</style>
</head>
<body>
<div class="div"></div>
<script type="text/javascript">
window.onload=function(){
var div=document.getElementsByClassName('div')[0];
var timer=null;
function larger(obj,goal,speed){
var offsetwidth=obj.offsetWidth;
var offsetheight=obj.offsetHeight;
if(offsetwidth<goal&&offsetheight<goal){
obj.style.height=(offsetheight+speed)+'px';
obj.style.width=(offsetwidth+speed)+'px';
clearTimeout(timer);
timer=setTimeout(function(){
larger(obj, goal, speed);
},50);
}
else{
clearTimeout(timer);
}
}
div.onclick=function(){
larger(this, 400, 10);
}
}
</script>
</body>
</html>
