<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
<style type="text/css">
.message{
width:200px;
height:100px;
background-color:#CCC;}
</style>
</head>
<body>
<script type="text/javascript">
var node=document.createElement("p";)
node.classname="message";
var textnode=document.createTextNode("I love Javascript");
node.appendChild(textnode);
document.body.appendChild(node);
</script>
</body>
</html>
var node=document.createElement("p");才对，你的分号写进去了就不显示出来
classname应该写成className