var PrLoad= new Image() if (!PrLoad.complete) When we preload image, if it is already loaded, the onload will not fire. We should use PrLoad.complete for detecting if it is already loaded. The problem with ie9, is the PrLoad.complete not work properly. I have try to use window.onload event for manualy change image already loaded but undetected by ie9 but the problem is the onload event fire before all image preloaded will be loaded. So the preload will become useless in ie9. Someone know how can I solve this?