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 run-time error is raised.
• Objects are converted to strings.
• Strings are converted to numbers if possible. If not, a run-time 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.