                        課程
                    
                        /前端開發(fā)
                        
                            /JavaScript
                        
                        /JavaScript進階篇

我代碼已經(jīng)提交成功了,但是頁面上沒有顯示啊,為什么呀

<!DOCTYPE? HTML>
<html >
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>流程控制語句</title>
<script type="text/javascript">

?//第一步把之前的數(shù)據(jù)寫成一個數(shù)組的形式,定義變量為 infos

??? var infos = [
??????? ('小A','女','21','大一');
??????? ('小B','男','23','大三');
??????? ('小C','男','24','大四');
??????? ('小D','女','21','大一');
??????? ('小E','女','22','大四');
??????? ('小F','男','21','大一');
??????? ('小G','女','22','大二');
??????? ('小H','女','20','大三');
??????? ('小I','女','20','大一');
??????? ('小J','男','20','大三');
??????? ]

?//第一次篩選，找出都是大一的信息

?? var arr1 = [];
?? var n = 0;
?? for(var i=0;i<=infos.length;i++)
?? {
?????? if(infos[i][3]=="大一")
?????? {
?????????? arr1[n]=infos[i];
??????????? document.write(arr1[n]+"<br/>");
?????????? n=n+1;
?????? }
?????? }
??? document.write("大一人數(shù)："+arr1.length+"<br/>");

?//第二次篩選，找出都是女生的信息

??? for(i=0;i<=arr1.length)
??????? {
??????????? if(arr1[i][1]=="女")
??????????? {
??????????????? document.write(arr1[i][0]+"<br/>");
??????????? }
??????? }
</script>
</head>
<body>
</body>
</html>