if (something1 operator something2) { command }
elseif (something1 operator something2) { command }
else ( command }

By operator I mean the thing that compares something1 to something2
The common operators are:
== equal to
!= not equal to
< less than
> larger than
>= larger than or equal to
<= smaller than or equal to

isin string something1 is in string something2
isincs string something1 is in string something2 (case sensitive)

ison something1 is on channel something2
isop something1 is an op on channel something2
isvo something1 has a voice on channel something2

To use the oppisite of one of the operators, use a ! before it. For example, if we put !isop then it would mean if something1 is not and op on something2
There are other operators, to see them, look at the mirc help file. They aren't used much so I didn't want to waste time on them.

Now for a few examples. You can type this on the command like: //if (5 == 5) { echo -a Hey }. That's an easy one, but if you do it it will echo hey because 5 equals 5.
Here's one that uses else: //if (5 == 4) { echo -a no } | else { echo -a hey } That will echo hey because 5 doesn't equal 4.
Notice the | thing? That allows you to use multiple commands on one line. Since if and else are really seperate commands, they need to be seperated.
The above examples are for typing into the command like. They won't work on their own in aliases or remotes. The following will, and demonstrates if-then-else and variables in action.
If you want to see it work, copy and paste it in the alias section (the white /a on a green background at the top) then type /if.test in the status window...or any other window, it doesn't matter

if.test {
set %number 1
:loop
if (%number == 10) { echo -a %number | echo -a I counted to 10 | unset %number | halt }
else { echo -a %number | inc %number 1 | goto loop }
}

I'm sure you're wondering what the hell that loop thing is. I'll explain that after I'm done with the if-then-else. But I think it's pretty easy to figure out what it is, really...
Also, did you notice that there aren't any / before any of the commands? That's because you don't have to include them when you're working in the alias, popups, or remote boxes, although you can if you want.

The elseif is pretty straight forward. Here's an example built on the earlier example

if.test1 {
set %number 1
:loop
if (%number == 10) { echo -a %number | echo -a I counted to 10 | unset %number | halt }
elseif (%number == 5) {echo -a %number - half way there | inc %number 1 | goto loop }
else { echo -a %number | inc %number 1 | goto loop }
}

Goto and Loops

These are pretty easy to get as well.
Let's take a look at them in the above example...

if.test {
set %number 1
:loop
if (%number == 10) { echo -a %number | echo -a I counted to 10 | unset %number | halt }
else { echo -a %number | inc %number 1 | goto loop }
}

Basically, on the line that begins with 'else', you'll notice that bold part that says goto loop. A few lines above that (two, to be exact), you'll see :loop. The 'goto loop' part is telling it to go to the part called 'loop'. It doesn't have to be called loop. You can have 'goto hell' and put a ':hell' in there somewhere.

But something that has to be in there, is the : before the part, and only at the begining of that part. You notice on line 3 it says :loop and on line 5 it's goto loop. There is no : in the goto command, and that's the way it should be.

Timers