User Interface Design Patterns

Hi,

I don't have a specific ROR question but since clear design is on of ROR's main principles i'm hoping that some design folks can answer my question :).

I'm working on a webbased application which uses a lot of classic javascript. There are several screens with a lot of controls and the problem is that a modification to one controls (for example a dropdownlist) has influence on several other controls, which in turn can influence other controls.

For example I change dropdown A, this should load other values in dropdown B and C, because there are now other values in dropdown B and C, textbox D and E should be disabled, and checkbox F should be hidden.

I have several of these scenario's in the screens I'm working on and the code is slowly turning into "Big Ball of Mud" code.

Does anyone know if there are patterns/principles/books to solve this problem in a structured way so that I can prevent my code from becoming a unmaintainable mess?