Array
var p1 = new Array(1,2,3);
console.log(p1);
var p2 = ["red","yellow","green"]
console.log(p2);
var p3=[1,"name",true];
console.log(p3);
console.log(p3[1]); //输出结果为name
var p4 = new Array(3);
p4[0] = "1";
p4[1] = "2";
p4[2] = "3";
console.log(p4); //输出结果为["1","2","3"]
var arr=["123","b","c","d"];
console.log(arr.length); //输出结果为4
arr.length=3;
arr[99]="z";
console.log(arr.length); //输出结果为100
for(var i = 0; i<arr.length;i++){ //获取长度
console.log([i]); //输出结果为3
console.log(arr[i]); //输出结果为123,b,c,d
}