In addition, ELSE is not required. You can use it if you have a case where something should always happen if none of the IF/ELSEIF items are true. If you don't want anything to happen if those aren't true, then you don't need ELSE.
Many scripts, as mentioned, use IF's incorrectly (i.e. inefficiently). If you only use IF and not ELSEIF when you want only one item to match...
if ($1 == help) { command }
if ($1 == identify) { command }
if ($1 == quit) { command }
Then, mIRC has to check all of those even if the very first one is true. Obviously, if the first is true, the rest cannot be, so there's no reason to waste time checking them. If you used ELSEIF instead, mIRC doesn't have to check the comparisons.
Other scripts will use something like:
if ($1 == help) { command | halt }
if ($1 == identify) { command | halt }
if ($1 == quit) { command | halt }
That will work like ELSEIF's will and may even be slightly faster, but prevents adding any other script below those IF's. In most cases, you should just use ELSEIF. Besides, HALT in itself is often misused. In many cases, you should really use RETURN instead of HALT to stop a script as HALT can stop more than what you mean to stop.
