Rails 3 - paperclip with perloader

I use for upload my images Paperclip. I would like to ask you, if exist any gem or plugin for showing the preloader while the image is uploading (something like "56开发者_如何转开发% loaded").

it doesn't have to do anything with paperclip actually.

I am using mootools, with mootools I am using FancyUpload which has lots of options and is very well written and easy to debug, rewrite, extend etc...

When you use this, you get an "Ajax" upload with a progress bar.

if you are using jQuery, there are many plugins for that as well. it's very easy to integrate into the project.