JavaScript数组创建与核心方法详解

1 var a = new Array();

2 var b=new Array(20);

3 var c= new Array("red","green","white");

alert(b.length)  //20

c[3] = "purple";

alert(c.length) //4

c[25]="purple" //则从3到24的位置都被填充为null 

alert(c.length) //26

var d =["red","green","white"];

alert(d.length)  //3

d[25]="purplr"

alert(d.length); //26

var e =["red","green","white"];

alert(e.toString());  //"red,green,white"

alert(e.valueOf());  //同上

alert(e.join("-spring-"))  //"red-spring-green-spring-white"

var s="a,b,c";

var sS=s.split(",");//返回3个数组

var s="green"

var ss=s.split("")

alert(ss.toString())  //返回“g,r,e,e,n”

var　s=["a","b","c"];

var scon=s.concat("d","e");

alert(scon.toString())  //"a,b,c,d,e"

alert(s.toString())  //"a,b,c"

var s1=s.slice(1)  //s1为“b,c” 

var s2=s.slice(0,2) //s2为“a,b”