Why is "$" a valid function identifier? [duplicate]

Question

Possible Duplicates:
Can someone explain the dollar sign in Javascript?
Why would a javascript variable start with a dollar sign?

Why is it that I can assign a function to $ in Javascript, but not # or ^ ?

Answer 1

From the ECMA standard (Section 7.6)

The dollar sign ($) and the underscore (_) are permitted anywhere in an IdentifierName.