if

if (expression) action

“action” will execute if “condition” gives a non zero result

if ((DmxToBeatNewLevelLast = 0) & (DmxToBeatNewLevel  > 0)) BeatTap

Operators you can use

> >= < <= = <> & |

else if, else

You can’t, but you can do this kind of approach:

if ((extvalue(0,100) > 45) & (extvalue(0,100) < 55)) AnimationSpeed 100 //Fader 45-55% = 100% (nice big deadband)
if (extvalue(0,100) <= 45) AnimationSpeed extvalue (0,222)              //Fader 0-45% = 0-100%
if (extvalue(0,100) >= 55) AnimationSpeed extvalue (-260,400)           //Fader 55-100% = 100-400%

Or you can use GOTO and Exit to achieve the same thing:

if (MyValue = 123) GOTO ValIs123
DoSomething
Exit

ValIs123:
DoSomething
Exit