点击button div出现像下拉框那样的动画效果
<html>
<head>
<script type="text/javascript" src="/jquery/jquery.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$(".btn1").click(function(){
$("p").slideToggle('normal');
});
});
</script>
</head>
<body>
<button class="btn1">Toggle</button>
<p>This is a paragraph.</p>
</body>
</html>