Looking for a way to add a progress bar while generating and serving a CSV file via ajax? The database-heavy process is causing a delay, so I need a loader on the screen that disappears once the task is complete. It should be done with ajax or stay on the same page if possible. Currently using the code below, but struggling to determine when the download is finished in order to stop the progress:
var iframe = document.createElement("iframe");
iframe.src = (value.url);
iframe.style.display = "none";
document.body.appendChild(iframe);