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"]
];
//第一步把之前的数据写成一个数组的形式,定义变量为 infos
//第一次筛选,找出都是大一的信息
for(var i=0;i<infos.length;i++){
if(info[i][3]=='大一'){
document.write("大一学生的名字:"+infos[i][0])+"<br/>");
}
}
//第二次筛选,找出都是女生的信息
for(var j=0;j<infos.length;j++){
if((infos[j][3]=='大一')&&(infos[j][1]=='女')){
document.write("大一女生的名字:"+infos[j][0])+"<br/>");
}
}
infos中少了很多个逗号
infos里面有中文逗号 还有逗号你没写
document.write("大一学生的名字:"+infos[i][0])+"<br/>"); 【0】后面括号去掉
document.write("大一学生的名字:"+infos[i][0])+"<br/>");这个也是
符号说明都是英文状态下的 不是中文状态下 排版下 这个好找问题
全等于===试试