<!DOCTYPE HTML>
<html >
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>流程控制语句</title>
<script type="text/javascript">
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"]，
];
//第一步把之前的数据写成一个数组的形式,定义变量为 infos//
for(var i=0;i<infos.length;i++)
{
if(infos[i][1]=="女"&&infos[i][3]=="大一")
{
document.write(infos[i][0]);
}
}
//第一次筛选，找出都是大一的信//
//第二次筛选，找出都是女生的信息//
</script>
</head>
<body>
</body>
</html>
不知道哪里错了
["小J","男","20","大三"]，中括号后面的逗号是中文的...建议用DW写写里面有错误提示最少
for(i=0;i<10;i++){
if(infos[i][1]=='女'&&infos[i][3]=='大一')
document.write(infos[i][0]+'<br>');
}
逗号，你的逗号是中文的。