Why isn the ABCUpload progress bar working?
If you have ASP script debugging enabled the progress bar will not work. When debugging is enabled the script engine locks IIS down to one page at a time per session. This means that the progress bar cannot update. So if you want the progress bar to work you need to disable debugging. A similar situation can apply to ASP.NET as the Trace module can interfere with the progress bar. This should not be a problem for deployment since you should not have tracing enabled on a live server but it sometimes causes confusion when testing on development servers. Most proxy servers will recognize that the progress bar page is changing frequently and update it as required. However some proxy servers insist on serving the same out-of-date progress bar again and again rather than updating it as requested. Some proxy servers cache the entire request/upload before releasing it to the server in one fell swoop. So as far as IIS is concerned there’s a long wait and then it gets all the data in one go. The
