<script type="text/javascript" src="/js/jquery.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("#start").click(function(){
$("#box").animate({height:300},"slow");
$("#box").animate({width:300},"slow");
$("#box").queue(function () {
$(this).css("background-color","red");
$("#box").animate({height:100},"slow");
$("#box").animate({width:100},"slow");
$("#stop").click(function(){
<p><button id="start">Start Animation</button><button id="stop">Stop Animation</button></p>