To determine whether an array contains an element of a JS function implementation method _javascript tips

A method of realizing the JS function of 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<this.length && this[i]!=e; i++);
  Return! (i==this.length);
}

There's another Daniel who wrote this:

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 use method is:

var arr=["A", "B"];

Alert (Arr.in_array ("a"))

While minus iteration is said to be the fastest way in JS, do not know if it is true, from

Http://stackoverflow.com/questions/237104/javascript-array-containsobj

It's a very intense discussion here, and it's recommended to see if there is a way to use jquery, directly using jquery, refer to the address:

http://api.jquery.com/jQuery.inArray/

The above judge whether the array contains an element of the JS function implementation method is small series to share all the content, hope to give you a reference, but also hope that we support the cloud habitat community.