IF	… ELSE … END

This is the standard language set up.  It allows you to compare two numeric values in order to execute a comparison of a part of the script. You can also compare two text values.

IF A>5
	Execute if true
	…
ELSE
	Execute if false
	…
END

Numeric comparators 
<		less than
>		greater than
#		different from 
=		equal to
<=	less than or equal to
>=	greater than or equal to

Text comparators
Is									If text A is the same than text B
IsNot			 			If text A is different from text B
Contains				If text B contains text A
ContainNot		 If text B doesnt contain text A

Exemples

IF MouseH>Objet.Right
	xxx
ELSE
	xxx
END

IF TheName Contains "Mountains"
	xxx
ELSE
	xxx
END

This can also be produced to test predefined booleans : 
IF Macintosh
	Message GoMac
ELSE
	Message GoIBM
END

See : "Predefined variables" for more information on avalaible boolean values.