求问为什么无法运行？？
<!DOCTYPE html>
<html>
<head>
<title> new document </title>
<meta http-equiv="Content-Type" content="text/html; charset=gbk"/>
<script type="text/javascript">
function openWindow(){
var open=confirm("确认新建窗口打开网站吗？");
if(open==true){
var url=prompt("通过输入对话框，确定打开的网址","http://www.imooc.com");
if(url!=null){
window.open(url,'_blank','width=400px,height=500px,menubar=no,toolbar=no');
}else{
alert("再见！");
}
}else{
alert("再见！");
}
}
</script>
</head>
<body>
<input type="button" value="新窗口打开网站" onclick="openWindow()" />
</body>
</html>
<html>
<head>
<title> new document </title>
<meta http-equiv="Content-Type" content="text/html; charset=gbk"/>
<script type="text/javascript">
function openWindow(){
var open=confirm("确认新建窗口打开网站吗？");
if(open==true){
var url=prompt("通过输入对话框，确定打开的网址","http://www.imooc.com");
if(url!=null){
window.open(url,'_blank','width=400px,height=500px,menubar=no,toolbar=no');
}else{
alert("再见！");
}
}else{
alert("再见！");
}
}
</script>
</head>
<body>
<input type="button" value="新窗口打开网站" onclick="openWindow()" />
</body>
</html>
