Introduction to Logical Operations

VBScript Tutorials - Herong's Tutorial Examples

∟Numeric Comparison Operations and Logical Operations

∟Introduction to Logical Operations

This section provides a quick introduction of logical operations supported by VBScript: logical negation - Not, conjunction - And, disjunction - Or, exclusion - Xor, equivalence - Eqv, implication - Imp.

Logical operations are operations that:

Operates on one Boolean operand or two Boolean operands.
Produces a Boolean value by applying the logical operation specified by the operator.

There are 6 logical operations supported in VBScript:

Logical Conjunction (And): Resulting (True) if and only if both operands are (True).
Logical Disjunction (Or): Resulting (True) if one of operands is (True).
Logical Negation (Not): Resulting (True) if the operand is (False).
Logical Exclusion (Xor): Resulting (True) if and only if one of operands is (True).
Logical Equivalence (Eqv): Resulting (True) if and only if both operands have the same value.
Logical Implication (Imp): Resulting (True) if the second operand is (True) or both operands are (False).

To show you how logical operations work, I wrote the following script, logical_operation.html:

<html>
<body>
<!-- logical_operation.html
 - Copyright (c) 1998 HerongYang.com. All Rights Reserved.
-->
<pre>
<script language="vbscript">
   document.writeln(True And True)
   document.writeln(True Or True)
   document.writeln(Not True)
   document.writeln(True Xor True)
   document.writeln(True Eqv False)
   document.writeln(True Imp False)
</script>
</pre>
</body>
</html>