+ var fragment = getCopyOfNode(req.responseXML.documentElement.firstChild);
+ var img = fragment.getElementsByTagName('img')[0];
+ if (req.status === 200) {
+ // update
+ var existing = this.existingSlides[img.src];
+ if (existing) {
+ existing.src = existing.src + '?' + Math.random().toString();
+ }
+ slide.img.src = '';
+ slide.img.parentNode.removeChild(slide.img);
+ slide.img = undefined;
+ slide.parentNode.removeChild(slide);
+ }
+ else if(req.status === 201) {
+ // creation
+ img.onload = function(evt) {
+ // accelerate GC before replacing
+ slide.img.src = '';
+ slide.img.parentNode.removeChild(slide.img);
+ slide.img = undefined;
+ slide.parentNode.replaceChild(fragment, slide);
+ };
+ }
+ this.previewsLoaded--;
+ this.previewQueueLoadNext();