concat()
连接2个或者多个数组
var v1 = ["1","2","3"],v2 = ["4","5","6",9,8],v3;
v3 = v1.concat(v2,["m",99,8]);
slice();
var color=["red","blue","green","yellow","orange"];
var newColors=color.slice(1,2);
var newColors=color.slice(-2,4); //输出结果为yellow; 负数的时候总长度减去该负数 (3,4)
document.write(newColors); //输出结果为green;