javascript shows real ip ?

my question is can javascript reavle your real ip even if your behind a proxy. iv tried googling it but get different answers. what i do know is that it will show information about your pc. i know also that java can show the real ip. so can javascript reavle the true ip behind a proxy?

ps can there be a link to proof.

Hint:

use a proxy for little things, (+ make sure java is disabled). doesn't matter if you do the things above for a big thing… they'll catch you.