**VBScript Tutorials - Herong's Tutorial Examples** - v6.03, by Herong Yang

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>

Here is the output of this VBScript example script:

True True False False False False

No surprises in the output. But logical equivalence operation and logical implication operation are not commonly used operations.

Table of Contents

Introduction of VBScript - Visual Basic Scripting Edition

Variant Data Type, Subtypes, and Literals

►Numeric Comparison Operations and Logical Operations

Introduction to Numeric Comparison Operations

►Introduction to Logical Operations

String Operations - Concatenation and Comparison

Variable Declaration and Assignment Statement

Expression and Order of Operation Precedence

Statement Syntax and Statement Types

Array Data Type and Related Statements

Array References and Array Assignment Statements

Conditional Statements - "If ... Then" and "Select Case"

Loop Statements - "For", "While", and "Do"

"Function" and "Sub" Procedures

Inspecting Variables Received in Procedures

Error Handling Flag and the "Err" Object

Regular Expression Pattern Match and Replacement

scrrun.dll - Scripting Runtime DLL Library

IE Web Browser Supporting VBScript