[qwertyuiop]

Sweet,

function animate(id) {
	element = document.getElementById(id);
	duration = 100;
	start = new Date().getTime();
	setTimeout(function() {
	    now = new Date() - start;
	    progress = now / duration;
	        result = -1*progress;

	    element.style.backgroundPosition = result+"mm 0mm";
	    //element.innerHTML = result;
	        setTimeout(arguments.callee, 1);
	}, 10);
}

получилось так