var empty = {}; // An object with no properties
   var point = { x:0, y:0 }; // Two properties
   var point2 = { x:point.x, y:point.y+1 }; // More complex values
   var book = {
       "main title": "JavaScript", // Property names include spaces,
       'sub-title': "The Definitive Guide", // and hyphens, so use string literals
       "for": "all audiences", // for is a reserved word, so quote
       author: { // The value of this property is
           firstname: "David", // itself an object. Note that
           surname: "Flanagan" // these property names are unquoted.
       }
    };

var o = new Object(); // Create an empty object: same as {}.
var a = new Array(); // Create an empty array: same as [].
var d = new Date(); // Create a Date object representing the current time
var r = new RegExp("js"); // Create a RegExp object for pattern matching.

// here we define our method using "this", before we even introduce bob
var setAge = function (newAge) {
  this.age = newAge;
};
// now we make bob
var bob = new Object();
bob.age = 30;
// and down here we just use the method we already made
bob.setAge = setAge;
  
// change bob's age to 50 here
bob.setAge(50);

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

// Let's make bob and susan again, using our constructor
var bob = new Person("Bob Smith", 30);
var susan = new Person("Susan Jordan", 25);
// help us make george, whose name is "George Washington" and age is 275

var george = new Person("George Washington", 275);

// range.js: A class representing a range of values.
// This is a factory function that returns a new range object.
function range(from, to) {
    // Use the inherit() function to create an object that inherits from the
    // prototype object defined below. The prototype object is stored as
    // a property of this function, and defines the shared methods (behavior)
    // for all range objects.
    var r = inherit(range.methods);
    // Store the start and end points (state) of this new range object.
    // These are noninherited properties that are unique to this object.
    r.from = from;
    r.to = to;
    // Finally return the new object
    return r;
}
// This prototype object defines methods inherited by all range objects.
range.methods = {
    // Return true if x is in the range, false otherwise
    // This method works for textual and Date ranges as well as numeric.
    includes: function(x) { return this.from <= x && x <= this.to; },
    // Invoke f once for each integer in the range.
    // This method works only for numeric ranges.
    foreach: function(f) {
    for(var x = Math.ceil(this.from); x <= this.to; x++) f(x);
    },
    // Return a string representation of the range
    toString: function() { return "(" + this.from + "..." + this.to + ")"; }
};
// Here are example uses of a range object.
var r = range(1,3); // Create a range object
r.includes(2); // => true: 2 is in the range
r.foreach(console.log); // Prints 1 2 3
console.log(r); // Prints (1...3)

function Dog (breed) {
  this.breed = breed;
};

// here we make buddy and teach him how to bark
var buddy = new Dog("golden Retriever");
Dog.prototype.bark = function() {
  console.log("Woof");
};
buddy.bark();

// here we make snoopy
var snoopy = new Dog("Beagle");
/// this time it works!
snoopy.bark();

// original classes
function Animal(name, numLegs) {
    this.name = name;
    this.numLegs = numLegs;
    this.isAlive = true;
}
function Penguin(name) {
    this.name = name;
    this.numLegs = 2;
}
function Emperor(name) {
    this.name = name;
    this.saying = "Waddle waddle";
}

// set up the prototype chain
Penguin.prototype = new Animal();
Emperor.prototype = new Penguin();

var myEmperor = new Emperor("Jules");

console.log( myEmperor.saying ); // should print "Waddle waddle"
console.log( myEmperor.numLegs ); // should print 2
console.log( myEmperor.isAlive ); // should print true

// what is this "Object.prototype" anyway...?
var prototypeType = typeof Object.prototype
console.log(prototypeType);     // object

// now let's examine it!
var hasOwn = Object.prototype.hasOwnProperty("hasOwnProperty");
console.log(hasOwn);     // true

function Person(first,last,age) {
   this.firstname = first;
   this.lastname = last;
   this.age = age;
   var bankBalance = 7500;
  
   this.getBalance = function() {
      // your code should return the bankBalance
      return bankBalance;
   };
}

var john = new Person('John','Smith',30);
console.log(john.bankBalance);

// create a new variable myBalance that calls getBalance()
var myBalance = john.getBalance();
console.log(myBalance);

function Person(first,last,age) {
   this.firstname = first;
   this.lastname = last;
   this.age = age;
   var bankBalance = 7500;
  
   var returnBalance = function() {
      return bankBalance;
   };
       
   // create the new function here
   this.askTeller = function(){
       return returnBalance;
   };
}

var john = new Person('John','Smith',30);
console.log(john.returnBalance);
var myBalanceMethod = john.askTeller();
var myBalance = myBalanceMethod();
console.log(myBalance);

<html>
  <head>
    <script src="/rtl/jquery.js"></script>
    <script>
$(function() {                          // Function run when the page is loaded and DOM is ready
   $("#out").empty();               // Empties the HTML element with id="out" so if javascript is enabled the user will not see the "Please enable Javascript" message
   $("#in").keypress(function(ev) {
      $("#out").append(String.fromCharCode(ev.which));
   });
});
    </script>
  </head>
  <body>
    <h1 id="out">Please enable JavaScript</h1>
    <input id="in" type="text" />
  </body>
</html>

var main = function() {

}

$(document).ready(main);           // Loads and runs the main function when the page is loaded in the browser

$("#idname")

$(".classname")