Alert on updates

Hello, I’m new so please feel free to answer me RTFM or with an URL.
I tried to search for an answer to this but without result…

I wish to save various webpages I need to monitor (mostly, API references) and need to have some kind of “alert” (if only a color/style change) when the on line version get updated [hoping that it won’t happen for every banner change…].
Is there some way to do it? And the “banner” problem is, as I fear, blocking with regards to this need?

Thank you very much!

DEVONthink doesn’t support this but you could use DEVONagent Pro. Just create a search set, add the pages you want to monitor to the “Sites” tab and enable the “Only new pages” option.