When Ajax began to rise, there was quite a movement towards the prototype javascript library. This was also pushed by the great Ruby on Rails. Then came the visual effects of script.aculo.us. They look great, they really do. But for what price? Lots of KB of code.
alex@www:~/scriptaculous/$ du *.js -ch --apparent-size
23K controls.js
18K dragdrop.js
21K effects.js
28K prototype.js
899 scriptaculous.js
12K unittest.js
8.7K util.js
109K total
This is unacceptable for just a library. Most of these KB’s have to be downloaded and do not provide any functionality per-se. Broadband is not an argument here. To load or not to load 100kb is relevant.
I therefor really like the Sack of Ajax. It takes only about 4K:
alex@www:~/sack/$ du *.js -ch --apparent-size
3.9K tw-sack.js
3.9K total
Now this does not give us all the script.aculo.us stuff. For that case I suggest to just reuse the relevant parts of it. Just let the user download what you really use. Maybe one day we will see a reduced script.aculo.us. Or an alternative using Sack.
UPDATE: I now recommend to use protoype.js again, in a reduced version just for AJAX.