http://tasker.dinglisch.net/userguid...ctionedit.html :
" If*(Condition) Parameter
(most actions)
Allows specification of one or more conditions which must match if this action is to execute.
Single conditions consist of a*left-hand side(usually a variable name), an*operator*and a*right-hand-side*for example*%number, Equals, 1*indicates that the action will be executed if the variable %number has the value 1.
When more than one condition is specified, they must be combined via*And*(all conditions must be true),*Or*(at least one condition must be true) or*Xor*(exactly one must be true). These 'combiners' are calledboolean operators.
Usually, 2 or 3 conditions will be combined with all*Ands or all*Ors, but in order to allow more complicated logic, Tasker also offers*And*and*Or*in high-precedence versions. Of the 4 boolean operators which are available, the selection goes from low to high precedence ones.
The higher the precedence of a boolean operator, the further to the right it is shown. This enables the logical groups to be visualised.
Examples:
True | False & True | False*is the same as*( True | False ) & ( True | False )*so isTrue.
True & False | True & False*is the same asTrue & ( False | True ) & False*so is*False.
True & False | True |+ False*is the same asTrue & ( False | ( True | False ) )*so isTrue.
Note that the order of the conditions can mean that some conditions are never evaluated. For instance, when two conditions are present and the one above an*And*is*false*then the condition below it will never be evaluated. This can be advantageous if the second condition takes relatively more resources e.g. involves matching against a lot of text.
Please see the section on*Flow Control*for more information. "