Language Reference! Operator
Description
Used to perform logical negation on an expression.

Syntax
result = !expression

The ! operator syntax has these parts:

Part Description
result Any variable.
expression Any expression.

Remarks
The following table illustrates how result is determined:

If expression is Then result is
True False
False True

All unary operators, such as the ! operator evaluate expressions as follows:
  • If applied to undefined or null expressions, a runtime error is raised.
  • Objects are converted to strings.
  • Strings are converted to numbers if possible. If not, a runtime error is raised.
  • Booleans are treated as numbers (0 if false, 1 if true).
  • The operator is applied to the resulting number.
For the ! operator, if expression is nonzero, result is zero. If expression is zero, result is 1.