How to Create Graphical File Upload Progress Bars Using HTML5 and JavaScript
“In my previous posts, we discovered How to Use HTML5 File Drag & Drop, Open Files Using JavaScript and Asynchronously Upload Files Using Ajax. In the final part of this series, we cover the most exciting part of the process: graphical progress bars!
File upload progress bars provide essential user feedback but they’ve been notoriously difficult to implement. Until now that is. Both Firefox and Chrome support the XMLHttpRequest2 object which offers a progress event handler. But first, let’s consider how our progress bar will be implemented…”