One major reason of Firefox’s success is due to its abundant of interesting and innovative extensions that improve upon FireFox’s capability to ways unimaginable. FireFox has to be the first popular browser that manages to attract the the developer community to voluntarily develop large number of free extensions which subsequently realize Marc Andreessen’s revelation about “browser as the operating system”. Users no longer prefer monolithic browser where they have to wait impatiently for next release for some cool features. Rather the users now prefer to use extensible browser like Firefox to allow them to be more productive and cool using wide range of free powerful extensions. This means no more waiting for cool features to be built because chance is that there is some extensions somewhere that able to do the job.
Getting the XPI extension
So how does one download the XPI extension to peek its source code ? The answer is simple. One can easily download the XPI by manually saving it instead of clicking it to be installed. Whenever FireFox encounters a XPI file that user click on, it presume the user want to install the extension, therefore to save instead of installing it, just right-click on the link to call up “Save As …” function. One can then either rename the XPI as ZIP file (I prefer this way) or associate the zip manager (eg Winzip) with XPI extension.
Summarizing the steps
- Go to web page of the extension, usually by searching in https://addons.mozilla.org/en-US/firefox/
- Right-click on the button or that accompanies the extension or any URL link that reference XPI file (eg , and choose [Save Link As…] to call up the Save dialog box .
Rename the extension to zip so that zip manager can open it.
- Peek the source code/files of the extension using your favourite zip manager and see how the cool extension is been developed.
Yes, that’s it and it is really that simple ! So start peeking your next coolest extension !