//create contact model, no change event is fired when model is instantiated with data
var contact=new Backbone.Model({firstName:'John',lastName:'Doe',phone:'1-111-1111'});
//make a change
contact.set({phone:'2-222-2222'});
//verify a change has occured
console.log(contact.hasChanged()); //logs true
//get the attributes that have changed
console.log(contact.changedAttributes()); //logs {phone="2-222-2222"}