1、zInherit.js

/**http://www.nczonline.net/downloads*5、zInherit：使用zInherit.js库，给Object添加了两个方法：inheritFrom()和instanceOf()*instanceof()只是instanceof运算符的替代品，不适用原型链**//**baseClass多边形**/function Polygon(iSides) {     this.sides = iSides;}Polygon.prototype.getArea = function() {     return 0;}/**三角形**/function Triangle(iBase, iHeight) {     Polygon.call(this, 3); //3条边     this.base = iBase;     this.height = iHeight;}Triangle.prototype.inheritFrom(Polygon); //继承Triangle.prototype.getArea() { //覆盖Polygon的getArea()     return 0.5 * this.base * this.height;}/**平行四边形**/function Rectangle(iLength, iWidth) {     Polygon.call(this, 4);     this.width = iWidth;     this.length = iLength;}Rectangle.prototype.inheritFrom(Polygon); //继承Rectangle.prototype.getArea() { //覆盖Polygon的getArea()     return this.length * this.width;}/**特性一：动态原型支持*可避开原型链的限制，实现动态原型**/function Polygon(iSides) {     this.sides = iSides;     if (typeof Polygon._initialized == "undefined") {          Polygon.prototype.getArea() {               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); //使用inheritFrom()方法不重写prototype对象，只是为其加入方法而已          Triangle.prototype.getArea() {               return 0.5 * this.base * this.height;          }          Triangle.prototype._initialized = true;     }}/**特性二：多继承支持*inheritFrom()方法不替换prototype对象*要继承属性和方法，inheritFrom()必须与对象冒充一起使用**/function ClassX() {     this.messageX = "this is the X message";     if (typeof ClassX._initialized = "undefined") {          ClassX.prototype.sayMessageX() {               alert(this.messageX);          }     }     ClassX._initialized = true;}function ClassY() {     this.messageY = "this is the Y message";     if (typeof ClassY._initialized = "undefined") {          ClassY.prototype.shadowOffsetY() {               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() {               alert(this.messageZ);          }     }     ClassZ._initialized = true;}

/**http://devedge.netscape.com/*6、xbObject*不止支持继承，还支持方法的重载和调用超类方法的能力**///定义超类:_classes.registerClass("Grandpa");function Grandpa(pName) {     _classes.defineClass("Grandpa", prototypeFunction);     this.init(pName);   //init方法接受和构造函数相同的方法       function prototypeFunction() {          Grandpa.prototype.init = function(pName) {               this.parentMethod("init");  //parentMethod方法可以传递多个参数，第一个参数为要调用的父类方法名字，然后其他参数被传递给此方法               this.name = pName;            }          Grandpa.prototype.saynName = function() {               alert(this.name);             }     }}//定义继承: _classes.registerClass("Parent", "Grandpa");function Parent(pName, cNumber) {     _classes.defineClass("Parent", prototypeFunction);     this.init(pName, cNumber);   //init方法接受和构造函数相同的方法       function prototypeFunction() {          Parent.prototype.init = function(pName, cNumber) {               this.parentMethod("init");               this.name = pName;               this.number = cNumber;              }          Parent.prototype.sayMyName = function() {               alert(this.name);             }          Parent.prototype.sayMyNumber = function() {               alert(this.number);             }      }}/**xbObject：重载多边形***/_classes.registerClass("Polygon");function Polygon(iSides) {     _classes.defineClass("Polygon", prototypeFunction);     this.init(iSides);     function prototypeFunction() {          Polygon.prototype.init = function(iSides) {               this.parentMethod("init");               this.sides = iSides;          }          Polygon.prototype.getArea() {               return 0;          }     }}_classes.registerClass("Triangle", "Polygon");function Triangle(ibase, iHeight) {     _classes.defineClass("Triangle ", prototypeFunction);     this.init(iBase, iHeight);     function prototypeFunction() {          Triangle.prototype.init = function(ibase, iHeight) {               Triangle.parentMethod("init", 3);               this.base = iBase;               this.height = iHeight;          }          Triangle.getArea() {               return this.base * this.height;          }     }}_classes.registerClass("Rectangle", "Polygon");function Rectangle(iLength, iWidth) {     _classes.registerClass("Rectangle", "Polygon");     this.init(iLength, iWidth);     function protoypeFunction() {          Rectangle.prototype.init = function(iLength, iWidth) {               Rectangle.parentMethod("init", 4);               this.length = iLength;               this.width = iWidth;          }          Rectangle.prototype.getArea() {               return this.height * this.width;          }     }}