帮我看看是哪里出了问题，运行不出内容，实在找不到错在哪了？

源自：4-10 编程练习

<!DOCTYPE HTML>

<html >

<head>

<title>流程控制语句</title>

//第一步把之前的数据写成一个数组的形式,定义变量为 infos

var infos=new Array();

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"],

];

var info=new Array();

var num= 0;

//第一次筛选，找出都是大一的信息

//document.write("第一部分："+"<br/>");

for(var i=0;i<=infos.length;i++){

for(var j=0;j<=infos[i].length;j++){

if(infos[i][j]=="大一"){

info [num]=infos [i];

num++;

}

//第二次筛选，找出都是女生的信息

// document.write("第二部分："+"<br/>");

for(var i=0;i<=info.length;i++){

for(var j=0;j<=info[i].length;j++){

if(info[i][j]=="女"){

document.write(info[i][0]);

}

</script>

</head>

<body>

</body>

</html>

提问者：qq_慕粉909474 2019-01-03 17:43