JS Judgment object is not a number of common methods of array object, verify whether it is a digital

var arr = [1,2,3];//method One: function IsArray1 (arr) {  return Object.prototype.toString.call (arr) = = = ' [Object Array] ';} Method Two: Function IsArray2 (arr) {  return arr.constructor.name = = = ' Array ';} Method Three: Function IsArray3 (arr) {  return arr instanceof Array;}

Method Three considerations:

var myframe = document.createelement (' iframe '); Document.body.appendChild (MyFrame); var myArray = window.frames[window.frames.length-1]. Array; var arr = new MyArray (a,b,10); [a,b,10]   //MyArray The constructor has been lost, the result of instanceof will not be normal//The constructor is an arr instanceof Array that cannot be shared across the frame;//False

Determine if the number function Isnumber (n) {    

JS Judgment object is not a number of common methods of array object, verify whether it is a digital