Ninja.js

function Person(name, age, height, weight) {
	this.name = name;
	this.age = age;
	this.height = height;
	this.weight = weight;
}

Person.prototype.speak = function(speech) {
	console.log(this.name+": "+speech);
}

Person.prototype.jump = function() {
	this.height += 5;
}

Ninja = Object.create(Person);

Ninja.prototype.constructor = function (name, height, weight, beltColor) {
	this.beltColor = beltColor;
	Person.call(this, name, "infinity", height, weight); //Call the super constructor...
}

//Overload a function
Ninja.prototype.jump = function() {
	this.height += 15;
}


//Then, instantiate:
var p = new Person("John Doe",70,6.1,170);
p.speak("Hello world!");
//"John Doe: Hello world!"
p.jump();
alert(p.height);
//21.1

var n = new Ninja("Ninja Joe",6.2,170,'yellow');
//Uncaught TypeError: object is not a function
n.speak("Hiyah!");
n.jump();
alert(n.height);