give me a javascript to make image logon run

please give me script to make image logon run from left to right

thanks

 

        <img src="/image.jpg" id="run" style="position:absolute; left:0;" />
	<script type="text/javascript">
		var speed = 10; // 100 milliseconds
		function run_image(){
		 var run = document.getElementById("run");
		 var left = run.style.left?parseInt(run.style.left,10):0;
		 left++;
		 run.style.left = left + 'px';

		 if(left <= screen.availWidth)
		   setTimeout(run_image,speed);

		}
	run_image();
	</script>

HTML: