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']];
var?arr=[];
var?n=0;
????for(i=0;i<=infos.length;i++){
????????if(infos[i][3]=="大一"){
????????????arr[n]=infos[i];
????????????document.write(arr[n]+"<br>");
????????????n=n+1;
????????}
????}
alert(arr.length);這個alert里的arr.length是已經定義好的全局變量arr=[]的長度，那么for循環里的arr.length，也就是4該如何讓它彈出來？
訪問內部變量，好像！
慕粉3484744
2017-01-15 19:49:42
