为什么我这个代码运行后点击慕课网却没有跳转？？
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
</head>
<body>
<script type="text/javascript">
var main = document.body;
//创建链接
function createa(url,text)
{
var url,text;
var newa = document.createElement("a");
newa.setAttribute("href",url);
newa.setAttribute("style","color:red");
var newtext = document.createTextNode(text);
newa.appendChild(newtext);
main.appendChild(newa);
}
// 调用函数创建链接
createa("http://www.imooc.com","慕课网");
</script>
</body>
</html>
