Well.. I noticed how there's the possibility to record and show demo's in JK2. Though, being unfamiliar with the Q3 engine I don't know the commands for recording and playing up. Any help would be appreciated.

Also, is there any way of showing a demo utside of the game, i.e be able to view it straight from a website? Or do you need to convert it into an .avi, .mpg etc..

Try this, open up the console (shift + `)

Type
g_synchronousclients 1
record yourdemoname
g_synchronousclients 0

You should now be recording.

To stop open the console again, and type stoprecord.