调试不出来，帮我看看是怎么回事吧、、、谢谢、！
<!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 bianliang=confirm("是否打开新窗口？")；
if(bianliang==true){
var bianliang2=prompt("通过输入对话框，确定打开网址"，"http：//www.imooc.com/");
if(bianliang2!=null){
window.open('http：//www.imooc.com/','_la','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>
