Module-whitespace_restrictions is a project mainly written in PHP, it's free.
This module can be used to restrict the use of excessive whitespace in messages, by trimming down the whitespace at formatting time.
Module : @TITLE@ Version : @VERSION@ Author : @AUTHOR@
Sometimes users post messages that contain a lot of whitespace (e.g. to build up tension before posting a punch line.) When excessive whitespace is used, this can be terribly annoying for forum visitors
@DESCRIPTION@
Unpack the archive;
Move the directory "@MODULE_ID@" to the directory "mods" within your Phorum installation;
Login as administrator in Phorum's administrative interface and go to the "Modules" section;
Enable the module "@TITLE@".
Edit the settings for the module to setup the restriction that you want to use for your Phorum installation.