I thought there would already be an answer for this but I can't seem to find one..
How can I run a particular class method on all instances of this class in Javascript?

This has to be done in a situation where I do not know the names of the instances.
I think I could use some sort of static variable inside my class to store all instances, but this doesn't seem to exist in JS

So how to call my method on all existing instances of my class?
Note : just for clarification : I'm not speaking about CSS classes, I'm speaking about objects.

Edit : By Class in Javascript, I mean the creation of a new object on a function:

function something()

{

}



var instance = new something();