<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Dogadd2</title>
<script> 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(); Dog.prototype.sitting = false;
Dog.prototype.sit = function(){
if (this.sitting){
console.log(this.name + " is already sitting");
} else {
this.sitting = true;
console.log(this.name + " is start sitting");
}
};
//hasOwnProperty,如果属性是在实例中定义的返回true，如果是在圆型定义返回false var barnaby = new Dog("Barnaby", "Basset Hound", 55);
console.log(barnaby.hasOwnProperty("sitting"));
barnaby.sit();
console.log(barnaby.hasOwnProperty("sitting")); console.log(fido.hasOwnProperty("sitting"));
fido.sit();
console.log(fido.hasOwnProperty("sitting")); </script>
</head>
<body> </body>
</html>