/// from http://yehudakatz.com/2009/04/20/evented-programming-with-jquery/ via http://samizdat.cc/
$$ = function(node) {
    var data = $(node).data("$$");
    if (data) {
        return data;
    } else {
        data = {};
        $(node).data("$$", data);
        return data;
    }
};