Microsoft® JScript™ ! Operator | Language Reference Version 1

See Also

##### 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.
> - Boolean values 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.

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