This is different from a BBCode because BBCodes can only be used in posts. this is its own page,
The bigger problem with a BBCode is it is very dangerous (security wise) to give your users access to put arbitrary URLs inside an IFRAME- it defeats the entire purpose of not allowing users to use HTML code in posts.
An IFRAME bbcode is simple enough- just a very bad idea. If you still want it:
Replacement Code in BBCode Manager:
Code:
<iframe src={param}" width="100%" height="500">Your browser does not support IFRAMEs</iframe>
Then you would just use it like [IFRAME]http://www.vbulletin.org[/IFRAME].