为什么不输出呢?求救
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"]
];
//第一次筛选,找出都是大一的信息
var arr=[];
n = 0;
for (i=0;i<infos.length;i++){
if (infos[i][3]=="大一"){
arr[n]=infos[i]
}
document.write("大一学生:"+arr[n]);
n=n+1;
}
document.write("大一人数: "+arr.length+"<br/>");
//第二次筛选,找出都是女生的信息
for (i=0;i<arr.length;i++){
if (arr[i][1]=="女"){
docuemnt.write("大一女生:"+arr[i][0]);
}
}