VBScript Application Property

last modified April 9, 2025

The Application property in VBScript provides access to the global ASP Application object. It stores variables and objects available to all users of an application. This property is essential for maintaining state across multiple pages and users in web applications.

Application variables persist until the web server restarts or the application ends. They are shared among all sessions and users. This tutorial covers the Application property with practical examples to demonstrate its usage in ASP applications.

Application Property Overview

The Application property is automatically available in ASP pages. It represents the Application object that stores application-wide information. Variables stored in Application are accessible to all pages in the application.

Key features include locking mechanisms for thread safety and event handlers for application start/end. The Application object supports methods like Lock and Unlock for safe concurrent access. Understanding this property helps create robust web applications.

Storing and Retrieving Application Variables

This example demonstrates basic usage of the Application property to store and retrieve variables. Application variables are set using simple assignment and accessed through the Application object. They persist across page requests.

basic_application.vbs

’ Store application variables Application(“SiteName”) = “My Web Application” Application(“VisitorCount”) = 0

’ Retrieve and display values Response.Write “Welcome to " & Application(“SiteName”) & “<br>” Response.Write “Current visitors: " & Application(“VisitorCount”)

’ Increment visitor count Application.Lock Application(“VisitorCount”) = Application(“VisitorCount”) + 1 Application.Unlock

The script stores two application variables: SiteName and VisitorCount. These values can be accessed from any page in the application. The VisitorCount is incremented with proper locking to ensure thread safety during concurrent access.

Using Application Objects

The Application property can store objects in addition to simple values. This example shows how to store and retrieve a Dictionary object. Objects stored in Application must support apartment-threading or be marked as free-threaded.

application_objects.vbs

’ Create and store a Dictionary object Set Application(“UserSettings”) = Server.CreateObject(“Scripting.Dictionary”) Application(“UserSettings”).Add “Theme”, “Dark” Application(“UserSettings”).Add “Language”, “English”

’ Retrieve and use the object Set userPrefs = Application(“UserSettings”) Response.Write “Current theme: " & userPrefs(“Theme”) & “<br>” Response.Write “Language: " & userPrefs(“Language”)

’ Clean up (when no longer needed) Set Application(“UserSettings”) = Nothing

A Dictionary object is created and stored in the Application collection. The object is then retrieved and its values are displayed. Proper cleanup is shown when the object is no longer needed to free resources.

Application Locking Mechanism

This example demonstrates the importance of locking when modifying Application variables. The Lock and Unlock methods prevent concurrent access issues. They ensure only one client can modify Application data at a time.

application_locking.vbs

’ Initialize counter if not set If IsEmpty(Application(“PageHits”)) Then Application.Lock Application(“PageHits”) = 0 Application.Unlock End If

’ Safely increment counter Application.Lock Application(“PageHits”) = Application(“PageHits”) + 1 Application.Unlock

Response.Write “Total page hits: " & Application(“PageHits”)

The script initializes a page hit counter if it doesn’t exist. Each page view increments the counter within a locked section. This prevents race conditions when multiple users access the page simultaneously.

Application Events

The Application property is related to Application events in global.asa. This example shows how to handle Application start and end events. These events allow initialization and cleanup of application-wide resources.

global.asa

<SCRIPT LANGUAGE=“VBScript” RUNAT=“Server”> Sub Application_OnStart ’ Initialize application variables Application(“StartTime”) = Now() Application(“ActiveUsers”) = 0 End Sub

Sub Application_OnEnd ’ Cleanup code Set Application(“StartTime”) = Nothing Set Application(“ActiveUsers”) = Nothing End Sub </SCRIPT>

The global.asa file contains event handlers for application start and end. When the application starts, variables are initialized. When it ends, cleanup is performed. These events occur once per application lifetime.

Shared Configuration Settings

Application variables are ideal for storing configuration settings shared across all pages. This example shows how to maintain application-wide settings that can be accessed from any page. Changes affect all users immediately.

configuration_settings.vbs

’ Admin page - update settings If Request.Form(“UpdateSettings”) = “Yes” Then Application.Lock Application(“MaintenanceMode”) = Request.Form(“MaintenanceMode”) Application(“MaxUsers”) = CInt(Request.Form(“MaxUsers”)) Application.Unlock End If

’ Regular page - check settings If Application(“MaintenanceMode”) = “Yes” Then Response.Write “System is in maintenance mode. Please try again later.” Response.End End If

The admin page updates application-wide settings that affect all users. Regular pages check these settings to modify their behavior. This pattern is useful for system-wide configuration management in web applications.

Source

ASP Application Object Documentation

In this article, we have explored the Application property in VBScript, covering its usage and practical applications. From simple variable storage to complex object management, these examples demonstrate robust application state management. With this knowledge, you can enhance your ASP applications with proper shared state handling.

Author

My name is Jan Bodnar and I am a passionate programmer with many years of programming experience. I have been writing programming articles since 2007. So far, I have written over 1400 articles and 8 e-books. I have over eight years of experience in teaching programming.

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