Prototype, Constructor的使用和理解
JavaScript中Prototype的使用和实例
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title></head><body></body></html><script>(function(){console.log("=========prototype的用法和误区=========");var A = function(){};A.prototype.A1 = function(){console.log("A1");};A.prototype.A2 = [1,2,3];A.prototype.A3 = 1;var a1 = new A();var a2 = new A();a1.A2.push(4);a1.A3 = 2;console.log(a1.A3);//2console.log(a2.A3);//1console.log(a1.A2);//[1,2,3,4]console.log(a2.A2);//[1,2,3,4]/**由于prototype是模版不是对象拷贝而是链接的方式所以使用delete a1.A3, a1.A3并不会删除， 而是重新链上上一个值**/delete a1.A3;console.log(a1.A3);//1console.log(a2.A3);//1delete a1.A2;console.log(a1.A2);console.log("=========以下是继承部分=========");var B = function(){};B.prototype = new A();B.prototype.A3 = 10;var b1 = new B();console.log(b1.A3);//[1,2,3,4]console.log("=========以下是constructor部分=========");var C = function(){};C.prototype = {C1 : function(){}};var c = new C();console.log(a1.constructor ===A);//true/**C.prototype = {C1 : function(){}};等同于:C.prototype = new Object({C1 : function(){}});所以: c.constructor===C 为 false**/console.log(c.constructor===C);//falseconsole.log(c.constructor===Object);//trueconsole.log(C.prototype.constructor===Object);//true})();</script>