Make sure to disable the change event on the html input type file.

custom_backbone_datelink.js.coffee

(function($) {
  return $.extend($.fn, {
    customBackboneLink: function(model) {
      return $(this).find('input:not(:file)').each(function() {
        var el, name;
        el = $(this);
        name = el.attr("name");
        model.bind("change:" + name, function() {
          return el.val(model.get(name));
        });
        return $(this).bind("change", function() {
          var attrs;
          el = $(this);
          attrs = {};
          attrs[el.attr("name")] = el.val();
          return model.set(attrs);
        });
      });
    }
  });
})(jQuery);