onclick="return incrementClicks('14');"

WWW::Mechanize doesn't have a JS interpreter. You'll either have to do the equivalent of the JS yourself, or switch to something that processes JS. As for the later, I think there's a module that adds some measure of JS to WWW::Mechanize (can't remember the name), and there's a couple of other Mechanize modules that use JS-aware backends (e.g. IE, Mozilla).