在Wordpress选项页面中动态生成下拉

I've got a plugin I'm working on, part of which consists of a 'conditional' dropdown on the options page. Basically, I've got a dropdown with three options, and a second dropdown gets populated with info from the database depending on what is selected in the first dropdown. Problem is, I'm at a loss as to how to populate the second dropdown! I'm not really that great with AJAX, but it seems the likely solution. Any thoughts from the more seasoned devs out here?I've got a plugin I'm working on, part of which