gistfile1.js

function inherit(from, to) {
  function F() {}
  F.prototype = from.prototype;
  to.prototype = new F();
}

var Animal = function() {
  
};

Animal.prototype.eat = function() {
  console.log('eating');
};


var Person = function() {
  
};

inherit(Animal, Person);

Person.prototype.sayHi = function() {
  console.log('person saying hi');
};

var p = new Person();
p.eat();
p.sayHi();