Using Apply on another object by passing a new object in From http://javascriptissexy.com/understand-javascripts-this-with-clarity-and-master-it/

apply on object

var person = {
   firstName   :"Penelope",
   lastName    :"Barrymore",
   showFullName:function () {
// The "context"
console.log (this.firstName + " " + this.lastName);
 }
}

// The "context", when invoking showFullName, is the person object, when we invoke the showFullName () method on the person object.
// And the use of "this" inside the showFullName() method has the value of the person object,
person.showFullName (); // Penelope Barrymore

// If we invoke showFullName with a different object:
var anotherPerson = {
firstName   :"Rohit",
lastName    :"Khan"
};

// We can use the apply method to set the "this" value explicitly—more on the apply () method later.
// "this" gets the value of whichever object invokes the"this Function", hence:
person.showFullName.apply (anotherPerson); // Rohit Khan

// So the context is now anotherPerson because anotherPerson invoked the person.showFullName ()  method by virtue of using the apply () method