Using 'apply method' to call the constructor of the base class : Inheritance « Object Oriented « JavaScript Tutorial

1. JavaScript Tutorial
2. Object Oriented
3. Inheritance

function BaseClass(sColor) {
    this.color = sColor;
    this.sayColor = function () {
        alert(this.color);
    };
}

function SubClass(sColor, sName) {
    BaseClass.apply(this, new Array(sColor));

    this.name = sName;
    this.sayName = function () {
        alert(this.name);
    };
}

var objA = new BaseClass("red");
var objB = new SubClass("blue", "MyName");
objA.sayColor();
objB.sayColor();
objB.sayName();