想知道我删除后为什么不能添加
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-type" content="text/html; charset=utf-8" />
<title></title>
<style>
</style>
<script src="https://www.imooc.com/static/lib/jquery/1.9.1/jquery.js"></script>
</head>
<body>
<div id="second">I am fine.</div>
<button>点击清除</button>
<button id="try">点击添加</button>
<script>
$(function(){
var s
$("button:first").click(function(){
var s=$("#second").detach()
})
$("#try").click(function(){
$("body").prepend(s)
})
})
</script>
</body>
</html>
