jQuery animate background color slow

<!DOCTYPE html>
<html>
<head>
<title>jQuery Animate Example</title>
 <script type="text/javascript" src="http://code.jquery.com/jquery-2.1.4.min.js">
 </script>
<script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.11.2/jquery-ui.min.js"></script>

<script type="text/javascript">
       $(document).ready(function(){
          $("#animateButton").click(function(){
           $("#demoDiv").animate({backgroundColor:'yellow'},"slow");
          });
          });
</script>    
</head>	
<body>
<a href="javascript:void(0)" id="animateButton"> 
Click To Animate 
</a><br>
<br>
<p id="demoDiv" style="width:100px;height:100px;display:block;position:absolute;border:1px solid gray;"> Animate Me.</p>
</body>
</html>