為什么輸不出結果
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<html >
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>流程控制語句</title>
<script type="text/javascript">
?//第一步把之前的數據寫成一個數組的形式,定義變量為 infos
?var infos=new Array[('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') ]
?
?//第一次篩選，找出都是大一的信息
?var i;
?for(i=0;i<infos.length;i++){
? ? ?if(infos[i][3]=='大一'){
? ? ? ? ? ?document.write("大一的學生有："+infos[i][0]+"<br>");
? ? ?}
?}
??
?//第二次篩選，找出都是女生的信息
?var j;
?for(j=0;j<infos.length;j++){
? ? ?if(infos[j][3]=='大一'&&infos[j][1]=='女'){
? ? ? ? ?document.write("大一女生有:"+infos[i][0]+"<br>");
? ? ?}
?}
?
??
</script>
</head>
<body>
</body>
</html>
2017-12-21
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"] ]; for?(i?=?0;i<=infos.length;i++){ ????if(infos[i][3]?==?"大一"?&&?infos[i][1]?==?"女"){ ????????document.write(infos[i][0]+"<br/>"); ????} }2017-05-03
聲明數組那出現了問題，具體請去看數組聲明和多維數組那兩節課 。
還有就是到這還沒有學過json，樓上那個只會讓你越看越懵逼，不用去管他。
2017-04-23
數組不可以這樣定義的，數組里每一項應該作為一個對象比較合適，你看一下
<!DOCTYPE ?HTML>
<html >
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>流程控制語句</title>
<script type="text/javascript">
?//第一步把之前的數據寫成一個數組的形式,定義變量為 infos
?var infos=[
?{name:'小A',sex:'女',age:21,grade:'大一'},?
?{name:'小B',sex:'男',age:23,grade:'大三'},?
?{name:'小C',sex:'男',age:24,grade:'大四'},
?{name:'小D',sex:'女',age:21,grade:'大一'},?
?{name:'小E',sex:'女',age:22,grade:'大四'},?
?{name:'小F',sex:'男',age:21,grade:'大一'},
?{name:'小G',sex:'女',age:22,grade:'大二'},
?{name:'小H',sex:'女',age:20,grade:'大三'},?
?{name:'小I',sex:'女',age:20,grade:'大一'},
?{name:'小J',sex:'男',age:20,grade:'大三'}]
?
?//第一次篩選，找出都是大一的信息
?var i;
?for(i=0;i<infos.length;i++){
? ? ?if(infos[i]['grade']=='大一'){
? ? ? ? ? ?document.write("大一的學生有："+infos[i]['name']+"<br>");
? ? ?}
?}
??
?//第二次篩選，找出都是女生的信息
?var j;
?for(j=0;j<infos.length;j++){
? ? ?if(infos[j]['grade']=='大一'&&infos[j]['sex']=='女'){
? ? ? ? ?document.write("大一女生有:"+infos[j]['name']+"<br>");
? ? ?}
?}
?
??
</script>
</head>
<body>
</body>
</html>
2017-04-22
上面這么定義數組也可以吧