How can I add extension to browser from ExtJs application?

Chrome vs. Firefox Extension Security

• Please help me understand the difference (or non-difference) in safety for Firefox vs. Chrome browser extensions (plugins/add-ons). I'm about ready to move to Chrome for various reasons, but when I go to install (on Chrome) Chrome's versions of some of the extensions I was using on Firefox, some of the extensions give me a warning message about various types of personal data the extension would expose to the extension developer. A friend suggested that Firefox extensions do the same thing, but that Firefox isn't as good at warning you about it. I've read some explanations of the Chrome warnings already--http://productforums.google.com/forum/#!topic/chrome/Gnlg4W7HYv4 includes a good explanation of the Chrome side of things--but I'm really wondering about how Chrome's security in terms of extension data sharing differs from Firefox (or any other browser). I'd feel better sharing data with trusted plugin developers if I know that this data sharing is necessarily occurring in every browser and isn't just a flaw of the Chrome set-up. Thank you!

• Answer:

  Your friend is correct. All Firefox extensions have full access to all pages that you access. Chrome has more granular settings and notification for what extensions may access, e.g., they may choose to limit themselves to certain domains. This is (mostly) not a huge issue because most extensions for both Firefox and Chrome are written in Javascript, so their code can audited relatively easily. Bad extensions (mainly those that insert ads into pages) do sometimes creep in, however.