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Installing Firefox’s DOM Inspector After Not Installing It Initially

After receiving my computer back after having it serviced, I needed to download and install the applications that I use. I was initially quite pleased to see that the first application I would have installed, which is the Mozilla Firefox web browser, was already installed. However, I was not pleased to see that the DOM Inspector was not installed with it. And according to the article on the MozillaZine Knowledge Base on the DOM Inspector, when using the operating system that I use, it can only be installed when Firefox is first installed. And unfortunately, I only discovered that this extension was missing after installing many other Firefox extensions and after bookmarking many pages. Therefore, uninstalling then reinstalling Firefox was not something I wanted to have to do. There had to be a way around this. There had to be a way for me to install this extension on which I often rely, and without having to reinstall Firefox. So I decided to search the web for this method of installing the DOM Inspector after Firefox was installed, as I knew that this method had to exist.

At the time that I was looking for this method of installing the DOM Inspector, I wanted to have it installed as soon as possible. I needed it at the time, and I did not want to have to wait much longer to have what I needed. I already had to wait long enough after having to wait for my computer to be serviced. So I followed this first set of instructions I found on how to install the DOM Inspector this way. After following those instructions, I was once again able to use the DOM Inspector. Still, I had to wonder if there was a better method of installing it with Firefox already installed. Starting the installation of Firefox again, then copying files from a location where files were temporarily stored, then canceling the installation seemed more complicated than necessary. And later on, I did find a better way to install it, which coincidentally, was mentioned in the comments section of the blog post that contains these instructions that I followed.

It was when I upgraded to version of Firefox that I needed to discover how to install the DOM Inspector this way once again. Every other Firefox extension I had was considered compatible with this newer version of Firefox except for the DOM Inspector. And I found that the reason it was considered incompatible with this new version of Firefox was because of one line of information in its install.rdf file. This line of information indicated that the last Firefox version with which this extension was compatible was version So then I needed to once again find out how to reinstall the DOM Inspector, as I did not recall all details about how to install it while Firefox was already installed. And that was when I came across this set of instructions for installing the DOM Inspector. I found this set of instructions more straightforward and less unwieldy than the instructions I previously followed. It seemed more straightforward to use 7-Zip to open the Firefox setup file, copy the DOM Inspector’s contents to another folder, create an archive (with a file extension of .XPI) of those contents, and install the extension using that archive. This is something I never thought of doing, likely because I was too busy doing other work. However, I also decided to do something else to avoid having to install this extension again for as long as I use Firefox 2.

I did not want to go through this process after each update to Firefox. And I thought that there had to be a better way of keeping the DOM Inspector installed after installing it this way. I did not think I should have to keep going through this process simply because of a decision made at the time that Firefox was installed. Those who chose to have this extension installed at first do not need to do this, so why should I need to do this? And to accomplish this task of creating the illusion of the DOM Inspector being installed when Firefox was installed, I added the step of modifying the maxVersion property of the DOM Inspector’s install.rdf file so that it would work with subsequent versions of Firefox. I tested out this solution by uninstalling the DOM Inspector, then by reinstalling it using the instructions previously mentioned, although with a setup file for an older version of Firefox. And I found that after making the correct modifications to the install.rdf file before creating the archive, it could be installed, and would work with the newer version.

A guide to the entire process of installing the DOM Inspector with Firefox already installed is one that many might find useful. Therefore, a step-by-step how-to guide for doing this should be easily accessible. So I decided to include step-by-step instructions to follow for installing the DOM Inspector this way. I aspire to make this the kind of guide that I would have liked to have had when I decided that I needed the DOM Inspector without having to reinstall Firefox. And so below, I outline the process of installing the DOM Inspector after Firefox is installed, without having to go through certain installation or reinstallation processes again.

  1. Download the Firefox setup file. All you need to do is visit and then click the link to download this setup file.
  2. Go to the directory to which this setup file was downloaded.
  3. Then use file archiving software to view the contents of the setup file. 7-Zip, which can be downloaded from here, is software I would suggest for completing this task.
  4. By using this file archiving software, go to the directory titled optional, and then go to the directory titled extensions. You will then see a directory titled, which you can copy to a location of your choice.
  5. Then go to the location to which you copied this directory, and then open this directory.
  6. This step is optional, and can be skipped if you only need a relatively short-term solution to the problem of not having the DOM Inspector installed. Open the install.rdf file, then look for where <em:maxVersion> is listed. The version number of Firefox that was downloaded will be listed there, and you may change it so it will work with future versions of Firefox. I personally have changed this version number to 2.*.*.* so that I may not need to reinstall the DOM Inspector again for as long as I use Firefox 2. The reason I chose to enter this as the version number will be made more clear later in this entry.
  7. Use file archiving software such as 7-Zip to add the contents within the directory to a ZIP archive, although you will need to ensure that the archive has .XPI as its extension.
  8. Go back into Firefox. Then open this newly-created archive by entering the path to the archive in the address bar, or through another method of your choice. You will then be able to install the extension as you normally would. Therefore, you will then need to restart Firefox, and then you should be able to use the extension.

It may not be long until this set of instructions will be considered obsolete. Firefox 3 will soon be released, and the DOM Inspector will not be included with it. Instead, when one wants to use the DOM Inspector with it, one can simply download and install it, as it is already available here. In fact, although Firefox 3 Beta 5 is said to be for testing purposes only, quite a few people are already using it regularly. This is likely because it can be used without having to lose many extensions or configuration settings, according to this Lifehacker article. And many are also using Firefox 3 Beta 5 simply because it is already considered quite an improvement over Firefox 2. However, if you prefer to use Firefox 2 for now, and need to have the DOM Inspector installed after initially choosing not to install it, there is a way to install it. And if you can think of a solution to this problem that is better than the one I suggest here, then I encourage you to share it.