Class-based Inheritance in ES5

//constructor function Shape
function Shape(shapeName,shapeSides){
  this.name = shapeName
  this.sides = shapeSides
}
//defining the property "equalSides" on the prototype of Shape
Shape.prototype.equalSides = 'yes'
//displaying Shape.prototype
//it will show "equalSides" that is defined on the prototype
console.log(Shape.prototype)
//constructor function Rectangle
function Rectangle(shapeName,shapeSides,length,width){
  //call function invoked to inherit and initialize the properites of Shape for Rectangle
  Shape.call(this,shapeName,shapeSides)
  //properties of rectangle
  this.length = length
  this.width = width
}
//Setting Shape object to be the prototype of Rectangle
//so Rectangle can inherit Shape prototype properties
//through the new object created
Rectangle.prototype = Object.create(Shape.prototype)
//setting Rectangle's prototype constructor so that it points to itself 
Rectangle.prototype.constructor = Rectangle
//defining a method "area" on the prototype of Rectangle
Rectangle.prototype.getArea = function(){
  return this.length*this.width
}
//displaying Rectangle.prototype
//it will show getArea that is defined on its prototype
//and constructor function pointing to Rectangle itself
console.log(Rectangle.prototype)
//creating a Rectangle object instance
var obj = new Rectangle('Rectangle',4,3,5)
//displaying properties 
console.log("Name:",obj.name)
console.log("Sides:",obj.sides)
console.log("All sides are equal:",obj.equalSides)
console.log("Length:",obj.length)
console.log("Width",obj.width)
console.log("Area:",obj.getArea())