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December 2002

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Multizilla, More then just a tab browser addon.

By Mark Dodel© December 2002

One of the things I liked about the Opera web browser, once I understood it, was the tabbed browsing feature. I was pleased to see that feature added to the Mozilla web browser. I use it extensively now, but was hoping it could be more configurable. recently I heard about "MultiZilla" on usenet, though it was in a different context. People were promoting it as a quick way to change User Agent (the feature which reports your web browser's type and platform) on the fly. I soon learned from the MultiZilla web site that the User Agent switching was just one of the many features included in MultiZilla.

MultiZilla is a project started in conjunction with the Mozilla browser development. It dates from April 2001, which is rather young, even for an internet project. As with most Mozilla related development, it centers on Linux and windows, but since it is written in Mozilla's own languages - XUL/XBL-XML Binding Language, it will work on any platform that Mozilla runs on. In fact the MultiZilla Tab feature has been incorporated into the base Mozilla project. For example, you can double click the middle mouse button on a link in Mozilla and it will open up the URL in a new tab if you have Mozilla configured to do so.

Mozilla Tabbed Browsing Prefernces

My testing is with the Mozilla for OS/2 version 1.2b, which is currently the latest stable release. As of this writing (early November, 2002), the latest version of MultiZilla is v1.1.31 Beta 2, though the site states a new version should be out by November 18th. Installation of MultiZilla is relatively painless. First make a backup of your Mozilla /chrome/ directory. Note: There is no way to uninstall MultiZilla, other then returning to a backup or reinstalling Mozilla, so make sure you do this step. Then make sure you have Software Installationturned on in your Mozilla Edit -> Preferences -> Advanced menu. Next go to and click on the install link on that page (I used the one for Windows).

You will get a Mozilla text window asking if you are sure you want to give the web site permission to install the application. Click on Install and a status window pops up showing MultiZilla being installed. When its done (a few seconds) it will tell you to restart Mozilla.

MultiZilla adds a new category to the Mozilla Edit -> Preferences menu, MultiZilla which allows you to configure MultiZilla itself. Here you can Set the tab size, select top or bottom tab positioning, decide when to use a Tab for a new link, select what icons appear on the toolbar, and determine how to manage groups of tabs. you can also select to have all the tabs in your previous session loaded when you restart Mozilla.

So what are the features of MultiZilla?

Besides the added Tab configuration, MultiZilla adds a new toolbar (with the Google search box), A Quick Preferences Menu (which includes the User Agent switching menu) and a host of smaller features.

The MultiZilla Toolbar

One of the first differences you will notice after installing MultiZilla is the new Toolbar. For some this may be a waste of screen space, but you can easily hide/restore it using the [F12] key.

Multizilla Toolbar

You can select what you want to appear on the Toolbar in the Edit -> Preferences -> MultiZilla -> Buttons settings. You can also turn the toolbar off if you don't like taking up screen space.

The buttons on the Left side of the MultiZilla Toolbar are related to the Toolbar itself (Tab position, Hide/Show Tabs) and starting new tabs. Also provides quick access to the MultiZilla update page.

The middle portion of the Toolbar is initially empty. You can fill this in by installing the separate GoogleBox addon which installs by clicking on an install link on the MultiZilla Install page similar to MultiZilla itself. The GoogleBox provides a quick way to search the internet using the Google search engine. The drop down list gives you access to previous search criteria. Additional buttons give you more Google search options. If for some reason you don't like Google, you can hide/show the GoogleBox by toggling the [F2] key.

Finally the last 4 buttons to the right are for different ways of closing tabs (Close the current tab, close all but the current tab, close all tabs, and close selected tabs from the tab display list).

The Quick Preferences Menu

Quick Preference Menu IconBesides adding this QPref icon to the main Mozilla toolbar, the default install added it to the Personal toolbar and the MultiZilla toolbar. I had to hunt down and disable these additional icons in the Edit -> Preferences -> MultiZilla -> Buttons settings.

The Quick Preferences Menu gives you fast access to many items you may need to change. Most people like myself rarely if ever change. Still its nice to be able to get to things like Cookies Settings, Images Settings, Popup Settings, etc, without having to hunt it down in the Preferences. The Open Preference Editor item will list all the User preferences in your profiles prefs.js and lipref.js configuration files. I don't know much about these, so I didn't take any chances with screwing them up, but this tool looks like it could do a lot of damage to someone's profile if its not used right.

The HTTP UserAgent settings allow you to change the web browser name string reported to a web site you visit. This is handy when you need to go to a web site that insists on only allowing specific web browsers (usually IE on windows). You can fool them into thinking you are running what they think they require. It is not foolproof, as there are other methods to identify the browser and platform, but the UserAgent is the most used method. To see what your browser reports, you can go to Its interesting just to see all the information available to a web site if they want to go to the trouble of looking for it.

When you first start MultiZilla you have to define any UserAgent strings you want to use. They give an example of how to do this and several entries for Linux, windows and Mac browsers at I added the OS/2 entries myself. It required my editing the localstore.rdf file which was in my Warpzilla profile directory (the one with the made up name under your user profile directory. In my case its E:\Warpzillahome\Mozilla\Profiles\madodel\doy1u576.slt.). Yours of course will have a variation on this location based on where your Mozilla profile is located. To get back to the actual UserAgent (In my case that would be for Mozilla for OS/2 1.2b), just go back into the HTTP UserAgent settings and choose "Select default UserAgent identifier", which is only available for selection if you have changed the UserAgent.

Multizilla Quick Preferences - HTTP UserAgent settings

If you are only interested in the UserAgent switching, there are other Mozilla addons that do this without all the extra features. For one of these checkout Uabar -

The rest of the Quick Preference items are just fast ways of changing Mozilla browser preference settings like Proxy Settings, Cache settings and Security settings (Images, Cookies, JavaScript, Popups).

Other features of MultiZilla

Since MultiZilla is tab oriented, it is no surprise that several of its features revolve around tab usage.

One listed feature is the ability to drag and drop tabs to a different position. This doesn't appear to work in the OS/2 version of Mozilla, which isn't surprising since Drag and Drop is not fully implemented in Warpzilla.

All-in-all I am looking forward to future development in MultiZilla, as it adds new features.

Multizilla v1.1.31 Beta 2
Developer: MultiZilla -
Price: Opensource under the Mozilla Public License

Other links referenced:
  XML User Interface Language (XUL) -
  XBL - XML Binding Language -
  Mozilla for OS/2 -

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