How many times have you been on a web page and you selected a value in a drop down box, only to suddenly see the whole page refresh so that it can fetch values for another drop down box? I see it all the time in car web sites. You select the Make of the car and the whole page is reloaded to bring back all the corresponding Models. Then you select the Model and the whole page is reloaded again to bring back all the corresponding Trims. Annoying, isn't it? Some sites avoid this problem by preloading all the possible alternatives in memory. This works, but there are times when the amount of data is just too overwhelming for all the possible co..
