大神来帮忙看看？
<!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 a;
a=confirm("您好，您确认打开此窗口");
if (a==true)
{ var b=prompt("您好，请输入您要打开的窗口地址:");
if(b!=null)
{window.open(b,'_blank','wdith=400px,height=500px,menubal=no,toolbal=no');}
else
{window.open('http//:www.17173.com','_blank');}
}else{window.open('http//:www.17173.com','_blank');}
}
</script>
</head>
<body>
<input type="button" value="新窗口打开网站" onclick="openWindow()" />
</body>
</html>
我想在点击取消的时候，跳到另外一个我设定好的网址，该怎么办？
