请问为什么我写的不行
<!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("确认开网页吗?")};
if(open=true)
{var url=prompt("请输入网址"."http://www.baidu.com/")};
if(url!=null)
{window.open(url,"_blank",'width=400px,height=500px,menubar=no,toolbar=no'}
else
{alert("88!")}
else
{alert("88!")}
</script>
</head>
<body>
<input type="button" value="新窗口打开网站" onclick="openWindow()" />
</body>
</html>