Js function implementation method to determine whether an array contains an element _ javascript skills

The following small series will provide you with a js function implementation method to determine whether an array contains an element. I think this is quite good. Now I will share it with you and give you a reference. Let's take a look at it with xiaobian. Js function implementation method for determining whether an array contains an element

Array.prototype.contains = function(obj) {  var i = this.length;  while (i--) {    if (this[i] === obj) {      return true;    }  }  return false;}

Or

Array.prototype.contains = function(element) {  for (var i = 0; i < this.length; i++) {    if (this[i] == element) {      return true;    }  }  return false;}

Or

Array. prototype. in_array = function (e) {for (I = 0; I
 
  

  
Another Daniel wrote the following:

  

  
Array.prototype.S = String.fromCharCode(2);Array.prototype.in_array = function(e) {  var r = new RegExp(this.S+e+this.S);  return (r.test(this.S+this.join(this.S)+this.S));}
  

  
The usage is as follows:
  
Var arr = ["a", "B"];
  
Alert (arr. in_array (""))
  
It is said that while subtraction iteration is the fastest method in js. I don't know if it is true.
  
Http://stackoverflow.com/questions/237104/javascript-array-containsobj
  
The discussion here is very intense. We suggest you check it out. If jQuery is used, you can directly use the method implemented by jQuery. refer:
  
Http://api.jquery.com/jQuery.inArray/
  
The js function implementation method used to determine whether an array contains an element is all the content shared by Alibaba Cloud xiaobian. I hope to give you a reference and support for the script.