What does $$ mean in Javascript?

Question

I am looking at some javascript code and it has this in a function:

$$(\'.CssClass\').each(function(x) { .... } )

I get that the intent is

Answer 1

$ is a valid function name in javascript. So something defines a function $$ that takes a string looking for some class called .CssClass and returns a object where you call each on.

I know that jQuery defines a function called $ at least that does similar things.