问一下哪里错了,弹不出来
<!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("是否打开新窗口");
if (open==true)
// 新窗口打开时弹出确认框，是否打开
{var url==prompt("请输入网址")
if (url!null)
{window.open(url,'_blank','width=400,height=500')
else
{window.open('http://www.imooc.com','_blank','width=400,height=500')
}
}
}
}
</script>
</head>
<body>
<input type="button" value="新窗口打开网站" onclick="openWindow()" />
</body>
</html>
