对话框无反应，看了好久都没找出来问题，大家帮帮忙
<!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("打开？"
);
if(open==ture)
{var url=prompt
("是否打开网址","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>
