When I added collectives to Huffduffer, I wanted to keep the new feature fairly discrete. I knew I would have to add an add/remove device to profiles but I also wanted that device to be unobtrusive. That’s why I settled on using a small +/- button.
The action of adding someone to, or removing someone from a collective was a clear candidate for Hijax. Once I had the adding and removing working without JavaScript, I went back and sprinkled in some Ajax pixie-dust to do the adding and removing asynchronously without refreshing the whole page.
That was the easy part. The challenge lies in providing some meaningful and reassuring feedback to the user that the action has been carried out. There are quite a few familiar devices for doing this; the yellow fade technique is probably the most common. Personally, I like the Humanized Messages as devised by Aza Raskin and ported to jQuery by Michael Heilemann.
I knew that, depending on the page, the user could be carrying out multiple additions or removals. Whatever feedback mechanism I provided, it shouldn’t get in the way of the user carrying out another addition or removal. That’s when I thought of a feedback mechanism from a different discipline: video games.
Quite a few arcade games provide a discrete but clear feedback mechanism when points are scored. When the player successfully “catches” a prize, not only does the overall score in the corner of the screen update, but the amount scored appears in situ, floating briefly upwards. It doesn’t get in the way of immediately grabbing another prize but it does provide a nice tangible bit of feedback (the player usually gets some audio feedback too, which would be nice to do on the web if it weren’t to likely to get very annoying very quickly).
It wasn’t too tricky to imitate this behaviour with jQuery.
This game-inspired feedback mechanism feels surprisingly familiar to me. Sign up or log in to Huffduffer to try it for yourself.