JS 面向对象学习笔记

JS 面向对象学习笔记，整理一下：

//arguments装载向函数的传参，类似数组function add(){var res = 0;for(var i=0; i<arguments.length; i++){res += arguments[i];}return res;}//alert(add(1,2));//3//alert(add(1,2,3,4));//10//call()与apply()函数的应用var b1 = {v:'this is b1'};var b2 = {v:'this is b2'};function b(){alert(this.v);}/*b();//undifiend（this指代window）window.b(); //undifiend（this指代window）//call的第一个参数指代函数上下文（作用域）b.call(b1); //this is b1（this指代b1）b.apply(b2);//this is b2（this指代b2）*///类的修改【扩展】var d = new Number(5);d.add = function(b){//return this+b;return this+arguments[0];}//alert(d.add);//alert(d.add(6));//如何给所有的Number的实例都加上一个add方法//prototype属性，所有的类均具有//给Number类的prototype属性加了一个方法，这个方法可以应用与所有的Number实例Number.prototype.add = function(b){return this+b;}var c = 111;//链式语法//alert(c.add(100).add(200).add(300));//711//给Array类扩展一个indexOf方法Array.prototype.indexOf = function(v){for(var i=0; i<this.length; i++){if(this[i] == v){return i;}}return -1;}var ii = ['11', '22'];//alert(ii.indexOf('22')); //1//javascript 类function Animal(name){var dd = 1;//私有变量this.name = name; //公有变量this.age = 0;//定义私有方法function prMethod(){return dd;}//定义特权方法，可以访问私有、公有所有成员（变量dd不可销毁，闭包）this.sayHello = function(){dd++;var res = prMethod();return dd+':'+this.name+':'+this.age+':'+res;}}var i1 = new Animal('cat'); var i2 = new Animal('dog'); //alert(i1.sayHello()); //2:cat:0:2//alert(i2.sayHello()); //2:dog:0:2//此类扩展方法只能访问类的公有成员Animal.prototype.hello = function(){return this.name+':'+this.age;}//alert(i1.hello()); //cat:0//alert(i2.hello()); //dog:0//继承的实现function classA(name){this.name = name;this.showName = function(){return this.name;}}//类B继承类Afunction classB(name){//继承方法一/*this.bMethod = classA;this.bMethod(name);delete this.bMethod;*///执行classA函数，并将它的上下文【作用域】指向this(即为classB的实例)//继承方法二//classA.call(this, name);//继承方法三classA.apply(this, [name]);}var aa = new classA('aa');var bb = new classB('bb');//alert(aa.showName()); //aa//alert(bb.showName()); //bb//继承方法四function classC(){}classC.prototype = new classB('bb1');var cc = new classC();cc.name = 'cc';//alert(cc.showName()); //cc