Javascript

I know this is a php newsgroup, and the only way this post relates is because im using php to create the javascript... So please don't get too angry at me for being off topic. I don't know of any javascript newsgroups, if you do, I would greatly appreciate a reference. Now down to business: Is there a function that checks if an object exists in javascript? like an exists(document.all.object); type thing? Once again, i'm very sorry for the offtopic post, and I would appreciate any help, whether it be an answer, or a reference to a javascript newsgroup, or reference guide on the web.... anything. Thanks a lot Ed