Quirks mode and strict mode are the two 'modes' modern browsers can use to interpret your CSS. This page gives a short overview of the reasons for and the differences between these two modes.
If you're using popups, inevitably the time comes when you want to call scripts in another window. This page explains the basics of cross-window JavaScripting.
On this page I explain the basics of generating options in a select box and give a script for dynamic options: when the user selects something from one option box another is automatically filled with new data.