大牛看看这样行不？
<!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 numa=[
['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']
];
for(var i=0;i<numa.length;i++){
if(numa[i][3]=='大一'){
document.write(numa[i]+'<br>');
}else{
null;}
}document.write('大一四人'+'<br>');
for(var i=0;i<numa.length;i++){
if(numa[i][1]=='女'&&numa[i][3]=='大一'){
document.write(numa[i][0]+'<br>');
}else{null;}
}document.write('女生三人');
</script>
</head>
<body>
</body>
</html>
