gistfile1.js

// 1
var Person = function(name) {
  this.name = name;
}

// 2
Person.prototype.getName = function() {
  return this.name;
}

var thomas = new Person('Thomas');
var amy = new Person('Amy');

thomas.getName();

// 3
thomas.getName.call(amy);

// 4
delete Person.prototype.getName;