JS Singleton

singleton.js

var Singletone = (function () {
  var instance;

  return function Construct_singletone () {

    if (instance) {
      return instance;
    }

    if (this && this.constructor === Construct_singletone) {
      instance = this;
    } else {
      return new Construct_singletone();
    }

  };
}());