OK, I dig jEdit but have never done a search like your asking for, so I just tried it. CTRL-F brings up the search dialog, i typed in 'function' as the search word and choose 'search all buffers' and it poped up a dialog showing each occurence of 'function' in each buffer WAY COOL 🆒 , including line # on which it occurs and you just click on the one you want and your whisked away to that line in that buffer!
I use jEdit for everything: PHP, HTML, java, XML, etc... ( specifically I use jEdit version 4.1; I'd tried a later version but didn't like the way they moved some stuff around ).
Try jEdit. Its free. Its x-platform. Its low-carb.
-Tom.