<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Dog</title> <script> //给原型增加新属性和方法 function Dog(name, breed, weight){ this.name = name; this.breed = breed; this.weight = weight; } Dog.prototype.species = "Canine"; Dog.prototype.bark = function(){ if (this.weight > 25){ console.log(this.name + " Woof"); } }; var fido = new Dog("fido", "mixed", 38); fido.bark(); //给原型添加方法后所有的继承者都拥有该方法,属性也是如此 var barnaby = new Dog("Barnaby", "Basset Hound", 55); Dog.prototype.sit = function(){ console.log(this.name + " is now sitting"); }; barnaby.sit(); </script> </head> <body> </body> </html>