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The Complete Guide to the Visual InterDev 6.0 Debugging Tool

Microsoft Visual InterDev 6.0, released as part of the Visual Studio 6.0 suite in 1998, was a groundbreaking development environment for building web applications. At its core was a powerful integrated debugger. This tool allowed developers to step through complex web applications combining client-side scripts, server-side code, and database connections. Understanding how to use this classic debugging tool remains essential for maintaining legacy classic ASP (Active Server Pages) applications. Prerequisites for Debugging

Before you can debug an application in Visual InterDev 6.0, you must configure both your local environment and the web server properly.

IIS Configuration: Internet Information Services (IIS) must have App Debugging enabled. In the IIS manager, navigate to your application properties, select the Configuration button, and check the “Enable ASP server-side script debugging” box.

Server-Side Permissions: The developer account must belong to the “Debugging Users” group on the server hosting IIS.

Project Settings: In Visual InterDev, right-click your project, select Properties, and ensure the launch option is set to start debugging with the correct start page. The Debugging Environment

When you initiate a debugging session, Visual InterDev transitions into a dedicated debug layout. This layout provides several windows critical for inspecting your application’s state. The Watch and QuickWatch Windows

The Watch window allows you to monitor the values of variables and expressions over time. You can manually type variables into this window. If you need to check a value quickly without adding it permanently, select the variable in your code and press SHIFT + F9 to open the QuickWatch dialog. The Locals and Immediate Windows

The Locals window automatically displays all variables relevant to the current execution scope. This saves you from having to manually add watches. The Immediate window allows you to execute commands, change variable values on the fly, or print values using ? variable_name while the execution is paused. The Call Stack

Web applications often involve nested function calls or script execution moving across different include files. The Call Stack window displays the chain of function calls that led to the current line of code, allowing you to trace the execution path backwards. Server-Side vs. Client-Side Debugging

Visual InterDev 6.0 was unique because it could bridge the gap between code running on the web server and code running inside the user’s web browser. Debugging Server-Side Active Server Pages (ASP)

Server-side debugging targets code written in VBScript or JScript running within the Open ASP tags (<% … %>).

Set a breakpoint by clicking in the left margin next to a line of ASP code. Launch the debugger by pressing F5. Interact with the browser to trigger the page request.

Visual InterDev will intercept the execution on the server, flashing in your taskbar to show it has paused at your breakpoint. Debugging Client-Side Scripts

Client-side debugging targets scripts running directly in Internet Explorer. To debug client-side code, you must ensure that script debugging is enabled within Internet Explorer’s Advanced Internet Options. When a client-side breakpoint is hit, Visual InterDev attaches to the browser process (iexplore.exe), allowing you to step through browser-rendered scripts and inspect the Document Object Model (DOM). Execution Control Commands

Once your code hits a breakpoint, you can control its execution using standard debugging shortcuts:

F5 (Continue): Resumes normal execution until the next breakpoint is reached.

F10 (Step Over): Executes the current line of code and moves to the next line. If the line contains a function call, the function runs completely without stepping into it.

F11 (Step Into): Moves execution to the next line. If the current line is a function call, the debugger jumps inside that function.

SHIFT + F11 (Step Out): Executes the remainder of the current function and pauses immediately after the function returns to its caller. Common Troubleshooting Tips

Debugging in Visual InterDev 6.0 can be brittle due to its reliance on distributed COM (DCOM) components. If your debugger fails to attach, check the following:

Authentication Failures: Ensure you are not browsing your development site anonymously. The debugger requires Windows Integrated Authentication to verify your debugging permissions.

Process Isolation: If IIS is configured to run your web application in a separate memory space (High Isolation), ensure you attach the debugger to the correct mtx.exe or dllhost.exe process hosting your web application, rather than inetinfo.exe.

Just-In-Time (JIT) Debugging: If your application crashes without hitting a breakpoint, ensure JIT debugging is enabled in your system options so Visual InterDev can catch unhandled runtime exceptions.