Tech help?

It's like watching baby take his first steps, isn't it? I want to set up a pop-up menu to handle the various format options at left (saves space over listing them on the page). I can generate the menu easily enough, but I don't know how to make the selection actually execute. Can somebody fill me in? andrewcoyne.com: the open source website you design. UPDATE: Got it. Or very nearly. It works, at any rate.