prototypal_inheritance.js

// credit: http://davidshariff.com/blog/javascript-inheritance-patterns/

(function () {
    'use strict';

    /***************************************************************
     * Helper functions for older browsers
     ***************************************************************/
    if (!Object.hasOwnProperty('create')) {
        Object.create = function (parentObj) {
            function tmpObj() {}
            tmpObj.prototype = parentObj;
            return new tmpObj();
        };
    }
    if (!Object.hasOwnProperty('defineProperties')) {
        Object.defineProperties = function (obj, props) {
            for (var prop in props) {
                Object.defineProperty(obj, prop, props[prop]);
            }
        };
    }
    /*************************************************************/

    var human = {
        name: '',
        gender: '',
        planetOfBirth: 'Earth',
        sayGender: function () {
            alert(this.name + ' says my gender is ' + this.gender);
        },
        sayPlanet: function () {
            alert(this.name + ' was born on ' + this.planetOfBirth);
        }
    };

    var male = Object.create(human, {
        gender: {value: 'Male'}
    });

    var female = Object.create(human, {
        gender: {value: 'Female'}
    });

    var david = Object.create(male, {
        name: {value: 'David'},
        planetOfBirth: {value: 'Mars'}
    });

    var jane = Object.create(female, {
        name: {value: 'Jane'}
    });

    david.sayGender(); // David says my gender is Male
    david.sayPlanet(); // David was born on Mars

    jane.sayGender(); // Jane says my gender is Female
    jane.sayPlanet(); // Jane was born on Earth
})();