Chrome extension to execute script after Gmail sent

I am looking for a way to execute a script 开发者_如何转开发after a mail has been sent in Gmail using a Chrome extension. My take would be to restrict the extension to Gmail pages, then check for specific text (i.e. "Mail successfully sent") on the current page and eventually send a request.

Does anyone have ever heard of anything like this or knows a function or two from the top of their heads?

Thanks very much.

I haven't checked this in an extension, only in the web inspector but I'd use jquery to do something like this in a content script limited to mail.google.com/mail/

$('#canvas_frame').contents().find("div[role='navigation'] b:contains('Send'):parent").click(function() {console.log("gmail message sent")})