我今天做的尝试是,如何更它更像其他的语言一样的使用继承机制,多层继承和更方面的调用父类的构造。 我希望达到的效果: 复制代码 代码如下: function A(){ alert('a'); } function B(){ this.$supClass(); alert('b'); } extend(B,A); function C(){ this.$supClass(); alert('c'); } extend(C,B); var c = new C(); alert( c instanceof A ); //true alert( c instanceof B ); //true alert( c instanceof C ); //true
实例:
[Ctrl+A 全选 注:引入外部Js需再刷新一下页面才能执行] 我的extend是这样写的: 复制代码 代码如下: function extend(subClass,supClass){ var fun = function(){}, prototype = subClass.prototype; fun.prototype = supClass.prototype; subClass.prototype = new fun(); for(var i in prototype){ subClass.prototype[i] = prototype[i]; } subClass.$supClass = supClass; subClass.prototype.$supClass = function(){ var supClass = arguments.callee.caller.$supClass; if(typeof supClass == 'function'){ supClass.apply(this,arguments); this.$supClass = supClass; } }; subClass.prototype.constructor = subClass; return subClass; }
也许你会问,为什么不这样写: 复制代码 代码如下: function extend(subClass,supClass){ var fun = function(){}, prototype = subClass.prototype; fun.prototype = supClass.prototype; subClass.prototype = new fun(); for(var i in prototype){ subClass.prototype[i] = prototype[i]; } subClass.prototype.$supClass = function(){ supClass.apply(this,arguments); }; subClass.prototype.constructor = subClass; return subClass; }