Iain and Seb discuss the ins-and-outs of programming for creative applications. Html5 File Upload with Progress On Matlus. Html5 finally solves an age old problem of being able to upload files while also showing the upload progress.
Today most websites use Flash Player to achieve this functionality. Some websites continue to use the Html <form> with enctype=multipart/form-data, but with modification on the server side to enable showing users the upload progress. Essentially, what you need to do is hook into the server’s byte stream while it is receiving a file so you know how many bytes you’ve received and somehow convey that information back to the client browser, while it is still in the process of uploading the file. This solution works extremely well and is not fraught with the issues Flash Player causes (especially for large files).