如何将AJAX可折叠面板添加到HTML界面？

我正在尝试将AJAX可折叠面板添加到我的HTML页面。我知道这可以使用asp.net轻松完成AJAX可折叠面板，但是，我需要向现有HTML页面添加一个。任何想法有关于如何使用HTML、如何利用Javascript和AJAX做到这一点的建议，我都不胜感激！
  1. Add an onchange event to the first select
  2. In the handler place an Ajax call and populate the second select with the results
  3. The Ajax call should accept a single parameter (query string) and return key/value collection as Json

You might actually find this way is easier (with Jquery) than using the ASP.net Ajax stuff.