How to convert an “object” into a function in JavaScript?

Question

JavaScript allows functions to be treated as objects--if you first define a variable as a function, you can subsequently add properties to that function. How do you do the

Answer 1

var A = function(foo) {                                                                                                      
  var B = function() {                                                                                                       
    return A.prototype.constructor.apply(B, arguments);
  };
  B.prototype = A.prototype;                                                                                                 
  return B;                                                                                                                  
};