js inheritance

 

"text/javascript">

    function Person(username)
    {
        this.username = username

        this.sexy = function()
        {
            alert("Are u sexy?");
        }

        Person.prototype.pizza = function()
        {
            alert("Would you like a pizza?");
        }

        if (typeof Person.flag == "undefined")
        {
            alert("START");

            Person.prototype.getInfo = function()
            {
                alert("Here: " + this.username);
            }

            Person.flag = true;
        }
    }

    function women(username, age)
    {
        this.method1 = Person;
        //Without 'this', it does not work
        this.method1(username);
        delete this.method1;

        this.age = age;

        if(typeof women.flag == "undefined")
        {
            alert("women");
            women.prototype.sayWorld = function()
            {
                alert("woman: "+ username + " " + age);
            }
            women.flag=true;
        }
    }

    function Child(username, age)
    {
        Person.call(this, username);
    }

    function Child2(username)
    {
        //Similar as call, but from the second args, apply accept array
        Person.apply(this,new Array(username));
    }

    function Child3()
    {
    }

    Child3.prototype = new Person("CaoCao");
    Child3.prototype.slim = function()
    {
        alert("I am slim one");
    }

    function test(str)
    {
        //'this' is key, it points the object where the username should belongs
        document.writeln(this.username + " " + str);
    }

    var p1 = new Person("lisi");

    p1.getInfo();

    var woman = new women("beauty",29);
    alert(woman.username);
    woman.sexy();
    //the following 2 lines contains error
    //woman.getInfo();
    //woman.pizza();
    woman.sayWorld();

    //p1 and woman link to this in function test()
    test.call(p1,"F_CK");
    test.call(woman,"Do you still love me?");

    var child1 = new Child("tian",3);
    child1.sexy();

    var child2 = new Child2("tian",3);
    child1.sexy();

    var child3 = new Child3();
    child3.sexy();
    child3.slim();
    child3.getInfo();