What Is The Best Client Side Browser Library To Upload Multiple Files Over Http?

What is the best client side http library to upload multiple files? If it can handle directories that's a huge bonus. I'm looking for something that is open source or free. I'm looking for something like FTP, but that works over http, through the browser. Uploading multiple files through a normal HTML 4.x form is a bit of a hassle when it comes to uploading more than 5-6 files.

Feel free to share your personal experiences.



Uploadify is also another great multiple file uploader. It was built off of SWFUpload and they added new features to it.

Some of the features that I have found most helpful are:

The user can upload all the files at once using ctrl + clicking on all of the files

As the files are being downloaded a queue is displayed which shows the files being downloaded including a completeion bar.

As files are completed they are removed from the queue

It also allows you to specify which file types the user is able to download (they can only see the ones you choose)