var infos=new Arry[['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
for(var i=0;i<infos.length;i++){
if(infos[i][3]==='大一')
//第二次筛选,找出都是女生的信息
if(infos[i][1]==='女')
document.write(infos[i][0]+infos[i][2]+"</br>")
}
<!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"> //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=[["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 dy=new Array; var m=0; for(var i=0;i<infos.length;i++){ if(infos[i][3]=="大一"){ document.write(infos[i]+"<br/>"); dy[m]=infos[i]; m++; } } //第二次筛选,找出都是女生的信息 for(var j=0;j<=dy.length;j++){ if(dy[j][1]=="女"){ document.write(dy[j]+"<br/>"); } } </script> </head> <body> </body> </html>
var infos=new Arry[['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
for(var i=0;i<infos.length;i++){
if(infos[i][3]=='大一'){
//第二次筛选,找出都是女生的信息
if(infos[i][1]=='女')
document.write(infos[i][0]+infos[i][2]+"</br>")
}
}
第一个if加个大括号,把下面两句都框起来就好了,三个等号改成两个
if后面的等号是两个吧