Javascript中的继承机制5------zInherit

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zInherit库下载地址：http://www.nczonline.net/downloads/

演示代码：

<html><head><title>Example</title> <script type="text/javascript" src="zinherit.js"></script></head><body><script type="text/javascript">function Polygon(iSides) { this.sides = iSides;}Polygon.prototype.getArea = function () { return 0;}; function Triangle(iBase, iHeight) { Polygon.call(this, 3); this.base = iBase; this.height = iHeight;}Triangle.prototype.inheritFrom(Polygon);Triangle.prototype.getArea = function () { return 0.5 * this.base * this.height;}; function Rectangle(iLength, iWidth) { Polygon.call(this, 4); this.length = iLength; this.width = iWidth;}Rectangle.prototype.inheritFrom(Polygon);Rectangle.prototype.getArea = function () { return this.length * this.width;}; var triangle = new Triangle(12, 4);var rectangle = new Rectangle(22, 10);alert(triangle.sides);alert(triangle.getArea());alert(rectangle.sides);alert(rectangle.getArea());alert(triangle.instanceOf(Triangle));alert(triangle.instanceOf(Polygon));alert(rectangle.instanceOf(Rectangle));alert(rectangle.instanceOf(Polygon));</script> </body></html>

动态原型的支持：

<html><head><title>Example</title> <script type="text/javascript" src="zinherit.js"></script></head><body><script type="text/javascript">function Polygon(iSides) { this.sides = iSides; if (typeof Polygon._initialized == "undefined") { Polygon.prototype.getArea = function () { return 0; }; Polygon._initialized = true; }}function Triangle(iBase, iHeight) { Polygon.call(this, 3); this.base = iBase; this.height = iHeight; if (typeof Triangle._initialized == "undefined") { Triangle.prototype.inheritFrom(Polygon); Triangle.prototype.getArea = function () { return 0.5 * this.base * this.height; }; Triangle._initialized = true; }}function Rectangle(iLength, iWidth) { Polygon.call(this, 4); this.length = iLength; this.width = iWidth; if (typeof Rectangle._initialized == "undefined") { Rectangle.prototype.inheritFrom(Polygon); Rectangle.prototype.getArea = function () { return this.length * this.width; }; Rectangle._initialized = true; }}var triangle = new Triangle(12, 4);var rectangle = new Rectangle(22, 10);alert(triangle.sides);alert(triangle.getArea());alert(rectangle.sides);alert(rectangle.getArea());alert(triangle.instanceOf(Triangle));alert(triangle.instanceOf(Polygon));alert(rectangle.instanceOf(Rectangle));alert(rectangle.instanceOf(Polygon));</script> </body></html>

多重继承支持：（原型链不支持）

<html><head><title>Example</title> <script type="text/javascript" src="zinherit.js"></script></head><body><script type="text/javascript">function ClassX() { this.messageX = "This is the X message."; if (typeof ClassX._initialized == "undefined") { ClassX.prototype.sayMessageX = function () { alert(this.messageX); }; ClassX._initialized = true; }}function ClassY() { this.messageY = "This is the Y message."; if (typeof ClassY._initialized == "undefined") { ClassY.prototype.sayMessageY = function () { alert(this.messageY); }; ClassY._initialized = true; }}function ClassZ() { ClassX.apply(this); ClassY.apply(this); this.messageZ = "This is the Z message."; if (typeof ClassZ._initialized == "undefined") { ClassZ.prototype.inheritFrom(ClassX); ClassZ.prototype.inheritFrom(ClassY); ClassZ.prototype.sayMessageZ = function () { alert(this.messageZ); }; ClassZ._initialized = true; }}var objZ = new ClassZ();objZ.sayMessageX();objZ.sayMessageY();objZ.sayMessageZ();</script> </body></html>