Right now I am creating what might look like the classic schoolexample of Ajax:
Basically we are talking about three linked dropdown boxes - when selecting a value in the first box the second one should be enabled and filled and when selecting a value in the second box (Serie) the third box should be filled with values - depending on what's selected in the two other boxes.
First I created a Ajax solution for this. I.e when selecting a value in box 1 (År) I made a Ajax callback and retrieved values to fill in box 2 (serie). However, soon it struck me - when considering the total number of values in my specific scenario (about six values in the first box , max two in second box and about 3 in the third ) I felt I was overworking it making use of Ajax.
It makes sense to use Ajax for linked selectboxes when datasets are either large or extermely volatile, but in my cause: for my limited set of data I ended up generating (from my asp.net code) the Javascript needed for each scenarios - therefore I got NO postbacks at all.