var data = $('tbody');
console.log(data.filter(':first'), data.filter('tr.ay-sort-top'));
data.filter(':first').before(data.filter('tr.ay-sort-top'));
两次运行的控制台输出:
[<tr class="ay-sort-top">…</tr>] [<tr class="ay-sort-top">…</tr>]
[<tr>…</tr>] [<tr class="ay-sort-top">…</tr>]