function test(){}
console.log(typeof 1); // number
console.log(typeof test); // function 
console.log(typeof "yunxi"); // string
console.log(typeof undefined); // undefined

console.log(typeof []); // object
console.log(typeof /\d+/g); // object

console.log([] instanceof Array); // true
console.log(/\d+/g instanceof Array); // false

function isArray(obj) {
  return typeof obj == 'object' && obj.constructor == Array
}
// 测试demo
console.log(isArray([])); // true
var a = {"a":1};
console.log(isArray(a)); // false

var b = [1,2,3];
console.log(isArray(b)); // true
console.log(isArray(/\d+/g));// false

var iframe = document.createElement('iframe');
document.body.appendChild(iframe);
xArray = window.frames[window.frames.length-1].Array;    
var arr = new xArray("1","2","3","4","5");
//这个写法IE下是不支持的，标准浏览器firefox，chrome下有

console.log(arr); // 打印出 ["1", "2", "3", "4", "5"]
console.log(arr instanceof Array); // false 
console.log(arr.constructor === Array); // false

function isArray(obj) {
  return Object.prototype.toString.call(obj) == '[object Array]';
}
// 代码调用
console.log(isArray([])); // true
console.log(isArray([1,2,3])); // true

var iframe = document.createElement('iframe');
document.body.appendChild(iframe);
xArray = window.frames[window.frames.length-1].Array;    
var arr = new xArray("1","2","3","4","5");

console.log(arr); // ["1","2","3","4","5"]
console.log(isArray(arr)); // true