I made some modifications to the market scripts - parsing is greatly simplified, and they will now all accept a "callback" parameter which allows them to function as JSONp. This will allow them to be hosted on any site without worrying about cross-site-scripting security.

getBittrex: http://pastebin.com/bLKjsQAH
getAGX: http://pastebin.com/kSkc6h1f
getCoinnext: http://pastebin.com/1XXQ9hai