提供一组不同的可点击选项以提交相同表格的标准方法是什么？

I have a PHP-generated page which is displaying some data about a set of films. The page is updated using POST. The form only shows films starting with a particular letter. I want to present a set of clickable options at the top of the screen, each of which is a letter. So if you click on "B" it submits the form and re-draws the page showing only films that start with B. (I know, Ajax would be a better way to do this, but I'm trying to get something done quickly).I have a PHP-generated page which is displaying