apa.js

function Animal(name) {
  this.name = name;
  this.move = function() {
    return this.name;
  };
}
var a1 = new Animal('a');
var a2 = new Animal('a');
a1.move === a2.move
// false

// With prototype

function Animal(name) {
  this.name = name;
}
Animal.prototype.move = function() {
  return this.name;
}
var a1 = new Animal('a');
var a2 = new Animal('a');
a1.move === a2.move
// true