In coldfusion booleanVar == false and !booleanVar is not one. If you have a variable, If the boolean value is set like var booleanVar = true; or var booleanvar = false; then it does the same.

But if the value of this variable is set at any time blank e.g. var booleanVar ="";. Then ! booleanVar it’s give error in if condition e.g. if( ! booleanVar ). Because it just checks boolean vlaue.

But using ‘booleanVar == false’ it’s check not only the Boolean value it’s also check blank value. If there is a blank then it does not give the error. Since the value is blank, this condition will not match. e.g. if( booleanVar == false ).

This is most possible if the data comes from the database. It may come to boolean, null or blank values.