Hello ChromePlugins forum. My first time here, but hopefully not my last .

I'm considering making my first chromeplugin, but I'm a little confused by the restrictions that the google chrome documentation gives to extensions. Essentially I'm looking to allow users of my extension to use an additional feature to GMail. In order for the feature to work I'd need to trigger a function to run when the 'send' button is pressed in a gmail email (reply or compose mail). The function would then need to have access to a few data sources:
1) The 'To' field of the message/reply being composed
2) The google search feature
3) All the emails that the logged in user can use to send mail from

I have heard about an experimental Gmail API intended for greasemonkey scripts, which I believe can be of use, but I'm not sure just how much control this will give me.

I mainly want to develop this for myself but I'll probably put it up and make it available for anyone else that wants it.

The idea is for anyone who uses a single google account to manage lots of email accounts (by forwarding emails to a single account). When I click 'reply' to an email sent to another account, Gmail automatically selects to send the email from the account the original email was sent to. This is good, however, if I decide to write my own email to a specific person (or people) I often lack the presence of mind to change which email I want to send it from. Often this leads to confusion as to which email is actually me and impersonation/trust issues. My plugin would take all emails in the To field, and search Gmail for conversations involving them (where they are either in the from or To fields), tally up the number of times they have communicated with each of my accounts, and then if I'm sending an email from anything other then the most likely account that they prefer, it will pop up a message that will allow me to change my 'From' field.


So the question here is: Can this be done? And where should I begin the implementation (like what kind of special permissions, set up, manifest, etc. will I need)?

You can do anything you can in JavaScript. So really I'd say the answer is "likely".
The only complicated part of that that I can foresee is searching all the old email, you would likely need to hack around gmail a bit to see what you would need to AJAX request to get those emails' to/from/cc fields.
Other than that it sounds like pretty basic DOM manipulation. Also, I've never heard of a gmail greasemonkey API, but I wouldn't worry about it too much. Chrome doesn't have greasemonkey specifically anyway, so unless what you heard about was specifically for Chrome, don't bother with it.

Thanks for the response Waha. I'll see if I can get it working on my own.