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Venkman – Mozilla’s debugger

The Mozilla debugger, Venkman (named after the character Peter Venkman of the

Ghostbusters

movies),

is a free utility for Mozilla-based browsers (including Firefox). To install, open up your Mozilla browser

and go to

http://www.hacksrus.com/~ginda/venkman/

. At this address, you find a list of all the

Venkman builds. Click the Install link next to the latest version. You are prompted to continue the instal-

lation because Venkman is an unsigned Mozilla plugin. Click Install Now. Restart the browser and you

notice a new entry under the Tools

Web Development menu.

Running

To run Venkman, click Tools

Web Development

JavaScript Debugger to manually open the win-

dow. When you do so, the Venkman window automatically loads all the files containing JavaScript into

the debugger.

You can also use the

debugger

command in your code. It works with Microsoft’s Script Debugger. Any

time you include the

debugger

command, the debugger opens up at that line of code and stops execution.

Unlike Internet Explorer, Mozilla never asks you if you’d like to debug an error.

The Window

The Venkman window (Figure 14-14) is much more complicated than the Microsoft Script Debugger, but

also a lot more powerful.

The window is made up of several smaller windows (or views) containing various information about

the scripts you are inspecting. Each view is made up of several common components, as illustrated in

Figure 14-15.

The Microsoft Script Debugger is, ironically enough, buggy. On machines using

Windows 2000 and later, the Script Debugger seems to have problems staying acti-

vated. It’s not uncommon to use the debugger during one Windows session, shut

down the computer, and return only to find that the menu items in Internet Explorer

have disappeared. If this happens, go into Internet Options and click on the

Advanced Tab. Select the check box labeled Disable Script Debugging and click the

Apply button. Then, uncheck the check box and click the OK button. Most of the

time, this re-enables the debugger.

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Error Handling

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