bind.js

var Person = function(name) {
  this.name = name;
};

var sayHello = function() {
  console.log("Hello, my name is " + this.name);
};

var bob = new Person('Bob');
var paul = new Person('Paul');

var sayHelloBob = sayHello.bind(bob);
var sayHelloPaul = sayHello.bind(paul);

sayHelloBob();  // Hello, my name is Bob
sayHelloPaul(); // Hello my name is Paul