ensures a handler is run before any other registered handlers, independent of the order in which they were bound. Requires jQuery > 1.7

bindFirst

$.fn.bindFirst = function(which, handler) {
      // ensures a handler is run before any other registered handlers, 
      // independent of the order in which they were bound
      var $el = $(this);
      $el.unbind(which, handler);
      $el.bind(which, handler);

      var events = $._data($el[0]).events;
      var registered = events[which];
      registered.unshift(registered.pop());

      events[which] = registered;
    }