<!DOCTYPE html> <title>Reference of testcases for background-position-x animations</title> <style> #test { height: 100px; width: 100px; background-repeat: no-repeat; background-image:url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABkAAAAZCAMAAADzN3VRAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAAZQTFRF/wAAAAAAQaMSAwAAABJJREFUeNpiYBgFo2AwAIAAAwACigABtnCV2AAAAABJRU5ErkJggg==); /* a 25x25 px red box */ background-position-x: 50%; } </style> <div id="test"></div>