<!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(shù)據(jù)寫成一個(gè)數(shù)組的形式,定義變量為?infos?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"]????];?//第一次篩選，找出都是大一的信息
??for(var?i=0;i<9;i++){
???????if(infos[i][3]==="大一"){?????
???????document.write(infos[i][0]);?????}?}?//第二次篩選，找出都是女生的信息
??for(var?i=0;i<9;i++){????
?????????if(infos[i][1]==="女"){????
??????????document.write(infos[i][0]);?????}?}
??????????</script>
??????????</head>
??????????<body>
??????????</body>
??????????</html>
2018-08-05
其實(shí)二維數(shù)組那個(gè)問題也能這么寫吧，只是你的代碼都是出于一些小問題，待優(yōu)化:
<!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(shù)據(jù)寫成一個(gè)數(shù)組的形式,定義變量為?infos ? ?//第一次篩選，找出都是大一的信息 ? ?//第二次篩選，找出都是女生的信息 ? ?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?(var?i?=?0;?i?<?infos.length;?i++)?{ ??????????if?(infos[i][3]?==?"大一")?{ ??????????????if?(infos[i][1]?==?"女")?{ ??????????????????document.write("大一的女生有:"?+?infos[i][0]?+?"<br>"); ??????????} ??????} ??} </script> </head> <body> </body> </html>2018-08-05
首先，把for循環(huán)里的i<9替換成i<infos.length；其次，你這個(gè)還沒變成二維數(shù)組；再來，你的if判斷里有三個(gè)=....應(yīng)該改成兩個(gè)=；還有一點(diǎn)小問題，數(shù)組里的數(shù)字可以不加引號(hào)，，還有你的代碼重復(fù)了，應(yīng)該把兩個(gè)for循環(huán)里的內(nèi)容合并起來，if判斷按照題目來應(yīng)該嵌套