Can someone explain how to implement the jQuery File Upload plugin?

Question

EDIT (Oct 2019):

6 years later and jQuery File Upload is clearly still driving folks insane. If you\'re finding little solace in the answers here, try a se

Answer 1

I also struggled with this but got it working once I figured out how the paths work in UploadHandler.php: upload_dir and upload_url are about the only settings to look at to get it working. Also check your server error logs for debugging information.