js的数组申明

 //数组的3种申明方法,如下example
 //数组是一种object类型 通过typeof 来检查

 //example 1
 var arr= new Array("h","k","M","c");

 console.log(typeof arr);//object
 for( var i in arr){
     console.log(arr[i]);
 }

 //example 2
 var arr1=Array("hello","你好","大海");
 console.log(typeof arr1);//object
 for( var i in arr1){
     console.log(arr1[i]);
 }

 //example 3
 var arr3=["hello","你好","大海"];
 console.log(typeof arr3);//object
 for(var i in arr3){
     console.log(arr3[i]);
 }

 //example 二维数组
 var arr4=["hello","你好","大海"]
     arr4[]=['这是哪里'];

     console.log(arr4[][]);