Inheritance(Chapter 5 of JavaScript: The Good Parts)

code 1 var Mammal = function (name) {
2 this.name = name;
3 };
4
5 Mammal.prototype.get_name = function () {
6 return this.name;
7 }
8
9 Mammal.prototype.says = function () {
return this.saying || '';
};

var myMammal = new Mammal('Herb the Mammal');
var name = myMammal.get_name();
alert(name);

var Cat = function (name) {
this.name = name;
this.saying = 'meow';
};

Cat.prototype = new Mammal();
Cat.prototype.purr = function (n) {
var i, s = '';
for (i = 0; i < n; i += 1) {
if (s) {
s += '-';
}
s += 'r';
}
return s;
};

Cat.prototype.get_name = function () {
return this.says() + ' ' + this.name + ' ' + this.says();
};

var myCat = new Cat('Henrietta');

alert(myCat.says());
alert(myCat.purr(5));
alert(myCat.get_name());