{{* Force the browser to reload an image from the server instead of the cache. based on an answer from http://stackoverflow.com/a/22429796/3343347 Usage: Set $imgUrl to the src url you want to be re-fetched from the server *}} <script> $(document).ready( function() { forceImgReload("{{$imgUrl}}"); } ); {{* * find and return any existing img tags with a matching src url, and set them to an intermediate * src url so they can later be reverted back once the cached version has been updated. *}} function prepareImagesForReload(srcUrl) { var result = $("img[src='" + srcUrl + "']").get(); for (i = 0; i < result.length; i++) { {{* * Set the image to a reloading image, in this case an animated "reloading" svg * Ideally this wont be displayed long enough to matter. *}} result[i].src = "data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100' preserveAspectRatio='xMidYMid' class='uil-reload'%3E%3Cpath fill='none' class='bk' d='M0 0h100v100H0z'/%3E%3Cg%3E%3Cpath d='M50 15a35 35 0 1 0 24.787 10.213' fill='none' stroke='%23777' stroke-width='12'/%3E%3Cpath d='M50 0v30l16-15L50 0' fill='%23777'/%3E%3CanimateTransform attributeName='transform' type='rotate' from='0 50 50' to='360 50 50' dur='1s' repeatCount='indefinite'/%3E%3C/g%3E%3C/svg%3E"; } return result; } function restoreImages(srcUrl, imgList) { for (i = 0; i < imgList.length; i++) { imgList[i].src = srcUrl; } } function forceImgReload(srcUrl) { var imgList; var step = 0; var iframe = window.document.createElement("iframe"); // Hidden iframe, in which to perform the load+reload. {{* Callback function, called after iframe load+reload completes (or fails). Will be called TWICE unless twostage-mode process is cancelled. (Once after load, once after reload). *}} var iframeLoadCallback = function(e) { if (step === 0) { // initial load just completed. Note that it doesn't actually matter if this load succeeded or not. step = 1; imgList = prepareImagesForReload(srcUrl); iframe.contentWindow.location.reload(true); // initiate forced-reload! } else if (step === 1) { // forced re-load is done restoreImages(srcUrl, imgList); if (iframe.parentNode) iframe.parentNode.removeChild(iframe); } } iframe.style.display = "none"; window.parent.document.body.appendChild(iframe); {{* NOTE: if this is done AFTER setting src, Firefox MAY fail to fire the load event! *}} iframe.addEventListener("load", iframeLoadCallback, false); iframe.addEventListener("error", iframeLoadCallback, false); iframe.src = srcUrl; } </script>