Logical NOT Operator (!)

Microsoft Office JScript

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Microsoft® JScript® ! Operator  Language Reference 
Version 1 

See Also

Description
Performs 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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