I have need for this in two areas. One I am looking for a specific string of text and the other is to alert me a captcha was on the page. Both are really the same thing just different text strings. I am using Firefox and I have problems with my vision. I keep missing things. I thought maybe there was something out there that did this but after days of searching I came up with nothing. The closest thing was using greasemonkey to do it.
If you can help thank you very much!