創(chuàng)建數(shù)組：

1. var colors = new Array ();         //括號中可以填入項(xiàng)目數(shù)量

2. var colors = new Array ("red","blue","green");    //可以之間填入數(shù)組包含的項(xiàng)

PS：new可以省略，第二種的括號可以改為方括號。

讀取與設(shè)置數(shù)組的值：

用方括號，并填入基于0的數(shù)字

var colors = new Array ["red","blue","green"];
array [1] = "blue"    //顯示第二項(xiàng)
array [3] = "black"    //增加第四項(xiàng)

數(shù)組的項(xiàng)數(shù)保存在length屬性中：

var colors = new Array ["red","blue","green"];    //創(chuàng)建一個(gè)有三個(gè)字符串的數(shù)組
var name = [];                     //創(chuàng)建一個(gè)空數(shù)組
alert(colors.length);          //3
alert(colors.length);          //0

可以設(shè)置length屬性從數(shù)組的末尾移除項(xiàng)

var colors = new Array ["red","blue","green"];    //創(chuàng)建一個(gè)有三個(gè)字符串的數(shù)組
colors.length = 2;
alert(colors[2]);       //undefined 

colors有3個(gè)值，將length屬性設(shè)置成2會移除最后一項(xiàng)，再訪問時(shí)顯示undefined

添加新項(xiàng)

var colors = new Array ["red","blue","green"];    //創(chuàng)建一個(gè)有三個(gè)字符串的數(shù)組
colors.length = 4;
alert(colors[3]);       //undefined 

將length屬性設(shè)置大于數(shù)組項(xiàng)數(shù)，新增的項(xiàng)為undefined

var colors = new Array ["red","blue","green"];
colors[colors.length] = "black";  //在位置3添加黑色
colors[colors.length] = "brown";  //在位置4添加棕色

PS:數(shù)組的最后一項(xiàng)索引為length-1