Object.prototype
JavaScript是基于原型继承的,任何对象都有一个prototype属性。Object.prototype是所有对象的根,并且不可改变。
Object.prototype=null;
alert(Object.prototype);//[object Object]
Object与Object.prototype
Object继承于Object.prototype,增加一个属性给Object.prototype上,同时也会反应到Object上。如:
Object.prototype.nameStr="Object Prototype";
Object.prototype.getName=function(){return this.nameStr};
alert(Object.getName());//Object Prototype
Function.prototype与Object.prototype
由于Object.prototype是万物之根,所以Function.prototype也同时会继承Object.prototype的所有属性。如:
Object.prototype.nameStr="Object Prototype";
Object.prototype.getName=function(){return this.nameStr};
alert(Function.prototype.getName());//Object Prototype
Object/Function/String/Number/Boolean/Array与Date
Object/Function/String/Number/Boolean/Array与Date都是函数,函数又继承于Function.prototype, 所以更改Function.prototype一样会影响到Object/Function/String/Number/Boolean/Array与Date。如:
Function.prototype.initType='Function Type';
Function.prototype.getType=function(){return this.initType};
//alert(Object.getType());//Function Type
//alert(Date.getType());//Function Type
//alert(Number.getType());//Function Type
//alert(String.getType());//Function Type
//alert(Boolean.getType());//Function Type
alert(Array.getType());//Function Type
同样Function.prototype也会把所受Object.prototype的影响,传递给它的下一层级。如:
Object.prototype.nameStr="Object Prototype";
Object.prototype.getName=function(){return this.nameStr};
alert(Function.prototype.getName());//Object Prototype
alert(Array.getName());//Object Prototype
alert(Boolean.prototype.getName());//Object Prototype
Array/Array.prototype与Function.prototype/Object.prototype
Array是函数对象,受Function.prototype的影响,而Array.prototype不是函数对象,所不受Function.prototype的影响,但所有对象受Object.prototype的影响,所以Array.prototype也会受Object.prototype的影响。如:
Object.prototype.nameStr="Object Prototype";
Object.prototype.getName=function(){return this.nameStr};
//alert(Function.prototype.getName());//Object Prototype
//alert(Boolean.prototype.getName());//Object Prototype
Function.prototype.initFun=function(){
return 'Function.prototype.initFun';
}
alert(Array.initFun());//Function.prototype.initFun
var arr=['a','b'];
alert(arr.getName());//Object Prototype
alert(arr.initFun());//Error: arr.initFun is not a function
alert(arr.initFun);//undefined