为什么我的“创建”链接按钮无效呢？
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;
charset=gbf-32">
<title>无标题文档</title>
</head>
<body>
<script type="text/javascript">
var main1 = document.body;
//创建链接
function createa(url,text)
{
var alink = document.createElement("a");
alink.setAttribute("href",url);
alink.innerHTML=text;
main1.appendChild(alink);
return alink;
}
// 调用函数创建链接
main1.appendChild(createa("http://www.imooc.com","慕课网"));
</script>
<input type="button" value="创建" onclick="createa
("http://www.imooc.com","慕课网")"></input>
</body>
</html>
