w3schools
Search W3Schools :  
  
HOME HTML CSS XML JAVASCRIPT ASP PHP SQL MORE...   References Examples Forum About

VBScript Keywords

« Previous Next Chapter »

VBScript Keywords

Keyword Description
Empty

Used to indicate an uninitialized variable value. A variable value is uninitialized when it is first created and no value is assigned to it, or when a variable value is explicitly set to empty.

Example:
Dim x   'the variable x is uninitialized!
x="ff"   'the variable x is NOT uninitialized anymore
x=Empty   'the variable x is uninitialized!

Note: This is not the same as Null!!

IsEmpty

Used to test if a variable is uninitialized.

Example: If (IsEmpty(x)) 'is x uninitialized?

Nothing Used to indicate an uninitialized object value, or to disassociate an object variable from an object to release system resources.

Example: Set myObject=Nothing

Is Nothing Used to test if a value is an initialized object.

Example: If (myObject Is Nothing) 'is it unset?

Note: If you compare a value to Nothing, you will not get the right result! Example: If (myObject = Nothing) 'always false!

Null Used to indicate that a variable contains no valid data.

One way to think of Null is that someone has explicitly set the value to "invalid", unlike Empty where the value is "not set".

Note: This is not the same as Empty or Nothing!!

Example: x=Null 'x contains no valid data

IsNull Used to test if a value contains invalid data.

Example: if (IsNull(x)) 'is x invalid?

True Used to indicate a Boolean condition that is correct (True has a value of -1)
False Used to indicate a Boolean condition that is not correct (False has a value of 0)

« Previous Next Chapter »


Altova® MissionKit® - Integrated Suite of XML tools

Altova MissionKit

The Altova MissionKit, recent winner of the Jolt Product Excellence and Productivity Award for Best Development Environment, is an integrated suite of tools ideal for:

  • XML development
  • Web & Web services development
  • Data mapping & integration
  • Rendering & publishing XML & database data
  • XBRL validation, taxonomy editing, transformation & rendering

The MissionKit for XML Developers includes XMLSpy®, MapForce®, and StyleVision® plus 3 additional tools for less than the price of 2.

Try all 6 products free for 30 days!

Download a fully-functional free trial

  Altova Missionkit


WEB HOSTING
Best Web Hosting
PHP MySQL Hosting
Top 10 Web Hosting
UK Reseller Hosting
Web Hosting
FREE Web Hosting
Top Web Hosting
Windows Hosting
WEB BUILDING
Download XML editor
FREE Flash Website
FREE Web Templates
Website Monetization
FLIGHT TICKETS
Find the cheapest flight
to any destination now!
EDUCATION
US Web Design Schools
HTML Certification
JavaScript Certification
XML Certification
PHP Certification
ASP Certification
STATISTICS
Browser Statistics
Browser OS
Browser Display
W3Schools.com HOME | TOP | PRINT | FORUM | ABOUT
W3Schools is for training only. We do not warrant the correctness of its content. The risk from using it lies entirely with the user.
While using this site, you agree to have read and accepted our terms of use and privacy policy.
Copyright 1999-2009 by Refsnes Data. All Rights Reserved.