Yes, it should be, but in reality the UI usually seems to see the least attention for optimization of this sort, for one, because I think it tends to have peop

Yes, it should be, but in reality the UI usually seems to see the least attention for optimization of this sort, for one, because I think it tends to have people working on it who aren't necessarily true programmers, they are more of designers who do some JavaScripting, and also the company is much more concerned with not wasting the memory on their own servers, they figure that if its just taking up load on a client machine its not as important. Its a bad approach and I will often refuse to use a site if it has bad client side performance / seems like a memory hog but thats just the way things are now