                        課程
                    
                        /前端開發
                        
                            /JavaScript
                        
                        /JavaScript入門篇

幫我看看哪里有錯誤，點擊不出現消息對話框

<!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?first=comfirm("打開新窗口？");
????????if(first==true){
????????//?通過輸入對話框，確定打開的網址，默認為?http：//www.xianlaiwan.cn/
????????????var?url=prompt("確定打開網址？","http://www.xianlaiwan.cn/");
????????????if(url!=null){
????????????????//打開的窗口要求，寬400像素，高500像素，無菜單欄、無工具欄
????????????????window.open(url,"_balnk","width=400,height=500,menubar=no,toolbar=no");
????????????}
????????}
????}
??</script>?
?</head>?
?<body>?
	??<input?type="button"?value="新窗口打開網站"?onclick="openWindow()"?/>?
?</body>
</html>