Microsoft Script Debugger Release Notes

Preview Release

© Microsoft Corporation, 1997

This document provides information about using the preview release of Microsoft Script Debugger, including tips for installing and using the debugger successfully, notes about features that are not completely implemented, and descriptions of known problems.

Important  Look for a more recent version of this information in the file Readme.htm, which is installed in the folder where the Microsoft Script Debugger (Msscrdbg.exe) is located.

Contents

Installing and Starting the Script Debugger

Using the correct version  Microsoft Script Debugger Preview works with the Beta 2 release of Microsoft Internet Explorer 4.0 or with the Beta 2 release of Internet Information Server 4.0. Because the Script Debugger is designed to be generic across script hosts, Setup does not check for specific versions of products being installed, so you must ensure that you are running the correct versions of these products. If you attempt to use the Script Debugger with earlier versions of Internet Explorer (such as Internet Explorer 3.0 or the Platform Preview release of Internet Explorer 4.0), or with earlier versions of Internet Information Server, the debugger will not work and could disrupt IIS service.

Uninstalling previous versions of the Script Debugger   If you installed the Script Debugger for Internet Explorer 3.0, you must uninstall that version before proceeding with this installation.

Using IE4 in browser-only mode  You can install Internet Explorer 4.0 either as a stand-alone browser or an integrated suite with shell updates and the Active Desktop. Although you can use it in either mode, it is highly recommended that you run the Script Debugger in browser-only mode for debugging.

Choosing an installation directory name  If you change the default directory for the Script Debugger while installing it, make sure that target directory does not contain a single quotation mark. If it does, the debugger might operate unreliably.

Uninstalling IIS  If you uninstall Internet Information Server 4.0, the uninstall process will also remove the Script Debugger, even if you installed the Script Debugger separately. You can reinstall the Script Debugger by running the IIS installation and choosing to install just the Script Debugger.

Running multiple instances  If you use more than one instance of Script Debugger at a time, unexpected results can occur. It is recommended that you run only one instance of the Script Debugger at a time.

Dragging documents onto the Script Debugger icon  You can start the Script Debugger by dragging a document onto the Script Debugger icon in Windows Explorer. However, in this version of the debugger, the document you dragged will not be loaded. You can load the document by choosing Open from the File menu.

Requesting documents that contain syntax errors  If you request a page that contains invalid syntax, and then start the Script Debugger by choosing Yes in response to the resulting error message, the Script Debugger might hang or generate a General Protection Fault.

Viewing Debugger Documentation

Displaying Help  To view the documention, choose Help Topics from the Help menu in the Script Debugger. Pressing F1 does not display Help in this version.

Starting a browser before displaying Help  Help is displayed in the default Web browser. If you are running Internet Information Server, start Internet Explorer 4.0 before choosing Help Topics from the Help menu. If the browser is not already running when you display Help, the debugger might display a blank window, and the Script Debugger might hang.

Viewing Help if no browser is installed on the server  If you are debugging on a server that has no browser installed, you might not be able to view Help, because Help is displayed in the default browser. However, if you have permission to access the Web server as a file server, you can try using a browser on another machine to view the Help file. Look for a file on the server called Caesar.htm, and use file protocol (file://), not HTTP protocol (http://).

Help file graphics  Graphics in the Help file might not match the current user interface. In addition, some graphics are missing in this version.

HTML Source Editor

Entering file names when opening HTML documents  When you choose Open from the File menu to open an existing document in the Script Debugger, you must provide a complete file name, including extension, in the File Name box.

Opening HTML documents from the Desktop in Windows NT  In Windows NT, when you open a file in the Script Debugger using the Open dialog box, you can display documents by selecting Desktop from the Look In list. However, in this version of the debugger, the content of the Open dialog box reflects the desktop setting for the default user, not for the current user.

Known editing issues  The following are additional known issues with the editor in this version of the Script Debugger:

• Opening large HTML documents can take several seconds.
• The current line number is not displayed while you are editing or debugging.
• When you start a new document, HTML text might not be colorized.
• If you maximize a window while editing in it, and then open an additional document, the maximized window is cascaded.
• Find and replace functions are not currently supported in the editor. The Edit menu contains Find and Replace commands, but these are not enabled.

Script Debugging in Internet Explorer 4.0

Viewing source in Notepad  In some instances, choosing Source from Internet Explorer's View menu invokes the Script Debugger and launches Microsoft Notepad to display the document. To return to expected debugging functionality, restart your machine.

Browsing a document after closing the debugger  If you finish a debugging session and close the Script Debugger, and then return to Internet Explorer and continue working with the document you were just debugging, the browser sometimes restarts the debugger.

Working with multiple documents  If you open two documents in two windows in Internet Explorer, you can debug only one of them. For example, if you try to set breakpoints in both documents, the second debugger session is not active. You must close the second session in order to continue debugging in the first.

Entering commands in the Command window  You can display the Command window at any time while the Script Debugger is open, but commands that you type into the Command window have no effect unless you are in break mode (are at a breakpoint or are stepping through code).

Problems debugging after executing Document.Write  Using the Document.Write statement can cause problems under several different circumstances:

• If a Document.Write statement is followed by a Stop (VBScript) or Debugger (JScript) statement, Internet Explorer can hang.
• If a Document.Write statement is followed by a breakpoint, the breakpoint is ignored.
• If you enter a Document.Write command in the Command window while at a breakpoint, the debugger might quit responding to commands.

Setting breakpoints on invalid lines  If you attempt to set a breakpoint on a line that does not contain script (such as a line of HTML code) the Script Debugger sets the breakpoint on the next valid code statement, even if that statement is many lines away from where you tried to set the breakpoint.

Displaying the line indicator correctly  The Script Debugger might not display the current line indicator properly in the following instances:

• If you are stepping through inline JScript code.
• If the document you are debugging is displayed in a frame.
• If you call a function from the Command window that contains a breakpoint.
• If you are debugging a document, move to a new document in the browser, and then use the browser's Back button to return to the document you were debugging. In this case a second instance of the debugger is opened, but the current line is not indicated.

Note  If the line indicator is not properly displayed, you can try stepping into the next line, which can restore the indicator.

Features not fully implemented  The following features are not fully implemented in this version of the Script Debugger:

• Copying and pasting  You cannot copy or paste text in the Command window.
• Viewing variable values  To see the value of a variable, use the Command window. The Script Debugger does not include a Watch window, as in some other debuggers. For more details, see the Script Debugger documentation.
• Setting breakpoints by clicking  To set a breakpoint, choose Toggle Breakpoint from the Debug menu, or press F9. You cannot set a breakpoint on a line by clicking in the margin to the left of the line, as you can in some environments.
• The Options dialog box contains Path and Virtual App boxes that are not functional.

Known issues when debugging client scripts  The following are additional known issues with using this version of the Script Debugger in Internet Explorer 4.0:

• If you are debugging a document, return to it and then refresh it, continue debugging it, refresh it again, and repeat this process, you might see an assertion error which causes the Script Debugger and Internet Explorer to hang.
• If you minimize a child window in the debugger, such as the Command window or Running Documents window, the Restore command on the Control menu is unavailable. To restore the minimized child window, maximize it, and then resize it by dragging its corners.

Script Debugging in Internet Information Server 4.0

Note Be sure to review the information under Script Debugging in Internet Explorer 4.0 as well.

Inspecting variables after a runtime error  If you invoke the debugger after a runtime error, the Command window cannot be used to inspect the variables values in an ASP page. However, you can still evaluate expressions using the default language.

Debugging after IIS has been shut down  If you shut down Internet Information Server while a debugging session is running, and then attempt to continue debugging, the Script Debugger will generate a General Protection Fault.

Editing documents that are being debugged   If you are viewing an .htm file from a server, and then open the same document by choosing Open from the debugger's File menu, you will not be able to save changes to the document. This problem occurs only if you request the file using http:// protocol. It does not occur if you open the file in Internet Explorer using file:// protocol.

Known issues when debugging server scripts  The following are additional known issues with using this version of the Script Debugger in Internet Information Server:

• If you enter the VBScript Stop command into the Command window while at a breakpoint, the debugger will hang.
• If you are at a breakpoint, open the Command window, and call a function repeatedly that is defined in a script on the page, the debugger might hang when you continue running the document.
• If you enter a command in the Command window that creates an object (for example, MyObj=Server.CreateObject(...) ), the debugger might display an assertion error and hang.
• Included files are not displayed in the Running Documents window, nor can you step into the source code of included files.

Debugging Java

Debugging Java  This release of the Script Debugger includes only limited support for debugging Java code. You cannot debug Java code on Internet Information Server. Debugging Java code on Internet Explorer 4.0 can result in unexpected errors.