Inheriting a parent class in JS. Instantiating parent class in prototype to make only instance methods to be available for child class.

inheritance.js

// Class generator
var Class = function(parentCls) {
  var Klass = function() {
    this.init.apply(this, arguments);
  };
  
  if(parentCls){
    var subClass = function(){};
    subClass.prototype = parentCls.prototype;
	  Klass.prototype = new subClass;
  }

  Klass.prototype.init = function() {};
  
  return Klass;
};

// Parent Class
var ParentClass = new Class;

ParentClass.prototype.method = function() {
  console.log('calling the parent method'); 
};

ParentClass.prototype.variable = 'a string!';

ParentClass.staticMethod = function() {
  console.log('parent\'s static method');
}

// Child Class
var ChildClass = new Class(ParentClass);

console.log('DA PARENT:');
var myParent = new ParentClass;
myParent.method();
ParentClass.staticMethod();
console.log('the variable: ', myParent.variable);

console.log('DA CHILD:');
var myChild = new ChildClass;
myChild.method();  // Will call parent function
console.log('child class should not inherit parent\'s static methods:', myChild.staticMethod);
console.log('the variable in child: ', myChild.variable);