I was happily using Jörn Zaefferer's jQuery autocomplete plugin but then I found out that it had been deprecated and I should instead use the jQuery UI's autocomplete plugin instead.
After "upgrading" I started getting suspicious. Is it actually worse than the old one?
First, about the CSS. If you're not already loading the jQuery CSS you would have to add an extra 21,000 bytes file (which loads 80Kb of images) as opposed to the old jquery.autocomplete.css which was only 810 bytes.
Secondly, the new jQuery UI Autocomplete plugin didn't support any nice highlighting so you have to write your own and it can quickly get ugly. I wrote one myself and it gets nasty and you have to do your own escaping.
Thirdly, if you just need the autocomplete you'll also need UI core, UI position and UI widget. The minified file weighs in on 19Kb. The packed jquery.autocomplete.pack.js weighs in on just 8Kb.
Fourthly, speed. The jQuery UI Autocomplete feels more sluggish in loading and rendering. Granted, in my work I often have Firebug switch on but just generally it feels slower when using. Perhaps I've made it extra slow with my hackish attempt to make it highlight.
But... Although the list of options available in the old Autocomplete the number of options available in the new jQuery UI Autocomplete seems pretty nifty too. You mileage will vary. Another benefit of the jQuery UI Autocomplete is that it now seems the more maintained project. I don't see a lot of activity but at least it doesn't say "Deprecated" like it does on the old Autocomplete.
Comments
We've published the source of our autocomplete fork here:
http://bitbucket.org/twanschik/nonrel-search/src/tip/search/media/search/
It provides a much better user experience. E.g., you can click, hold the mouse button, and move the cursor. In the original implementation this would select text. Now it behaves like the desktop counterpart. Also, when you click inside the text box it'll automatically open a little tooltip indicating that this text field has auto-completion. Too often this is far from obvious. Also, the text field has a mode in which it acts like a drop-down field with auto-completion.
I have many issues with the new official plugin as well.
For instance, the delay does not seem to work consistently - try setting up an autocomplete with a remote source, set the delay to say 3 seconds, then keep spamming any character key - the autocomplete should never trigger the ajax request, but after the initial 3 seconds, it triggers constantly.
or try hitting a space, then the autocomplete will trigger after every single character thereafter.
To be fair, a lot of that load is already cached by the browser.