Is there a way to add a method to all javascript functions without using the prototype library?

something along the lines of :

Function.prototype.methodName = function(){ 


  return dowhateverto(this) 

 };

this is what i tried so far but it didnt work. Perhaps it is a bad idea also if so could you please tell me why?

if so can I add it to a set of functions i choose

something like :

MyFunctions.prototype.methodName = function(){ 


  return dowhateverto(this) 

 };

where MyFunctions is an array of function names

thank you