Total newbie here... Question about calling java applet with php on vBulletin templat

[Marauder]

Hello folks! I'm totally new to all of this and don't grok much of it. Here's my problem: I'm trying to call up a chat-interface-applet using javascript. One of the parameters being called needs to be echoed out by php. It is the automatic user login that should draft the required data directly from the forum. However, I have met with little success in my attempts thus far. I tried inserting a simple <?php echo "$getusername[username]"; ?> in the value filed for the parameter, and it didn't evaluate the php code, instead generating html that read value="<?php echo ""; ?>". I'm still researching the problem (today is the first day I've ever used php or dealt with vBulletin), but maybe one of you could shoot me some pointers? It would be much appreciated.

Thanks for reading!