< html>
Example
function Shape(iSides) {
this.sides = iSides;
if (typeof Shape._initialized == "undefined") {
Shape.prototype.getArea = function () {
return 0;
};
Shape._initialized = true;
}
}
function Triangle(iBase, iHeight) {
Shape.call(this, 3);
this.base = iBase;
this.height = iHeight;
if (typeof Triangle._initialized == "undefined") {
Triangle.prototype.getArea = function () {
return 0.5 * this.base * this.height;
};
Triangle._initialized = true;
}
}
Triangle.prototype = new Shape();
function Rectangle(iLength, iWidth) {
Shape.call(this, 4);
this.length = iLength;
this.width = iWidth;
if (typeof Rectangle._initialized == "undefined") {
Rectangle.prototype.getArea = function () {
return this.length * this.width;
};
Rectangle._initialized = true;
}
}
Rectangle.prototype = new Shape();
var triangle = new Triangle(12, 4);
var rectangle = new Rectangle(22, 10);
document.write("triangle.sides:"+triangle.sides);
document.write("
");
document.write("triangle.getArea():"+triangle.getArea());
document.write("
");
document.write("rectangle.sides:"+rectangle.sides);
document.write("
");
document.write("rectangle.getArea():"+rectangle.getArea());