jquery animate（{background:'red'}）无效果？？？
<!DOCTYPE html>
<head>
<meta charset="utf-8">
<script type="text/javascript" src="../js/jquery-2.0.0.min.js"></script>
<script type="text/javascript">
$(document).ready(function()
{
$(".btn1").click(function (){
$("p:eq(0)").animate({
height : '300px',
background : 'red'});
});
$(".btn2").click(function () {
$("p:eq(0)").animate({
height : '100px'
})
})
})
</script>
</head>
<body>
<p style="background:#00B83F">This is a paragraph.</p>
<button class="btn1">Hide</button>
<button class="btn2">Show</button>
</body>
</html>
