javascript对数组的申明、访问、转换、遍历、排序

1.声明
     var arr = new Array();       //声明一个空数组
     var arr = new Array(10);     //声明一个10个长度的数组
     var arr = new Array("Alice", "Fred", "Jean");    //用值初始化数组
     var arr = ["Alice", "Fred", "Jean"];     //用值初始化数组
     var arr = [["A","B","C"][1,2,3]];    //声明一个二(多)维数组
   2.数组的访问
     arr[0] = "123";      //赋值
     var str = arr[0];    //获取
     arr[0][0] = "123";   //多维数组赋值
   3.数组与字符串间的转换
     var arr = ["A","B","C","D"];     //声明
     //数组按分隔符转换成字符串
     var str = arr.join("|");         //结果: "A|B|C|D"
     //字符串切割成数组
     arr = str.split("|");
   4.遍历数组
     for( var i=0; i<arr.length; i++ ){ alert(arr[i]); }
   5.排序
     var arr = [12,15,8,9];
     arr.sort(); //结果: 8 9 12 15
   6.组合与分解数组
     var arr1 = ["A","B","C","D"];
     var arr2 = ["1","2","3","4"];
     //奖两个数组组合成一个新的数组
     var arr = arr1.concat(arr2); //结果: ["A","B","C","D","1","2","3","4"]
     //将一个数组切成两个数组(参数1:起始索引,参数2:切割长度)
     var arr3 = arr.splice(1,3); //结果: arr3:["B","C","D"] arr["A","1","2","3","4"]
     //将一个数组切成两个数组,并在原数组补新值
     var arr4 = arr.splice(1,3,"AA"); //结果: arr4:["B","C","D"] arr["A","AA","1","2","3","4"]