Automatic removal of part of the text from the letter?

Question

gmail

Hello,
I'll start from afar. There is an office with mail on GMail. All internal correspondence is conducted there. In addition to it, Postini is used. That is, letters first fall into it and only then into GMail. The situation is as follows, another signature is automatically added to each letter, that is, the signature configured in GMail + automatic. The problem is that the automatic signature is too long and does not make any sense for internal correspondence. And in most cases, it takes 80% of the letter.
Yes, GMail automatically hides captions and duplicate text in threads. But it works somewhere in 3 out of 4 cases. For example, it breaks off during forwarding or when you get into correspondence somewhere in the middle.
In general, flipping through the sheets is pretty tired, and a solution is being sought. I want to get them out of sight, at least in Firefox. There is nothing suitable for this in Google Labs. For Firefox, there is a FoxReplace plugin that even works, with one annoying exception. The text is replaced only if you press the hotkey. It has an option to do a replacement on page load, but it doesn't work with ajax updates. Adblock won't help, because it inserts pure text at the tail of the letter, there is no separate block for it.
Are there any other options? Maybe UserScript? But there is no writing experience, except to correct / adjust to your needs.

Answer 1

Dig towards Greasemonkey
Here are examples for working with gmail