Expand/Collapse

http://www.ncdot.org/dmv/vehicle_services/registrationtitling/howToRegister.html

Hey guys, I was just wondering if anyone could shed some light on how these guys are doing this simple “expand/contract” +/- buttons for the paragraphs of text. It appears to be a simple html page, but I’ve never come across that code…?

edit my mistake, it looks like its javascript, which appears to be loading externally, so I can’t see it. how might one accomplish this?

Thanks in advance!
Fitz