// This example is from the book _JavaScript: The Definitive Guide_.    
// Written by David Flanagan.  Copyright (c) 1996 O'Reilly & Associates.
// This example is provided WITHOUT WARRANTY either expressed or implied.
// You may study, use, modify, and distribute it for any purpose.        

// This is a function. It uses the this keyword, so
// it doesn't make sense to invoke this function by itself; it
// needs instead be made a method of some object, some object that has
// "width" and "height" properties defined.
function compute_area() 
{
    return this.width * this.height;
}

// Create a new Rectangle object, using the constructor defined earlier
var rect =index.html new Rectangle(8.5, 11);

// Define a method by assigning the function to a property of the object
rect.area = compute_area;

// Invoke the new method like this:
a = rect.area();    // a = 8.5*11 = 93.5