Adding js variable to Ajax post data

I am trying to add the variable "val" to an existing list of Ajax data

            var val = $(this).val();
$.ajax({
    url: 'index.php?route=product/product/add',
    type: 'post',
    data: $('#product input[type=\'text\'], #product input[type=\'hidden\'], #product input[type=\'radio\']:checked, #product input[type=\'checkbox\']:checked, #product select'),

Any ideas if or how this could be done?