Are +0 and -0 the same?

Question

Reading through the ECMAScript 5.1 specification, +0 and -0 are distinguished.

Why then does +0 === -0 evaluate to true<

Answer 1

Wikipedia has a good article to explain this phenomenon: http://en.wikipedia.org/wiki/Signed_zero

In brief, it both +0 and -0 are defined in the IEEE floating point specifications. Both of them are technically distinct from 0 without a sign, which is an integer, but in practice they all evaluate to zero, so the distinction can be ignored for all practical purposes.