var xPos = 300;
var yPos = 200; 
var step = 1;
var delay = 30; 
var height = 0;
var Hoffset = 0;
var Woffset = 0;
var yon = 0;
var xon = 0;
var pause = true;
var interval;
var img1 = document.getElementById("img1");
if(img1 != null)
{
img1.style.top = yPos;
    function changePos() 
    {
	    width = document.body.clientWidth;
	    height = document.body.clientHeight;
	    Hoffset = img1.offsetHeight;
	    Woffset = img1.offsetWidth;
	    img1.style.left = xPos + document.body.scrollLeft;
	    img1.style.top = yPos + document.body.scrollTop;
	    if (yon) 
		    {yPos = yPos + step;}
	    else 
		    {yPos = yPos - step;}
	    if (yPos < 0) 
		    {yon = 1;yPos = 0;}
	    if (yPos >= (height - Hoffset)) 
		    {yon = 0;yPos = (height - Hoffset);}
	    if (xon) 
		    {xPos = xPos + step;}
	    else 
		    {xPos = xPos - step;}
	    if (xPos < 0) 
		    {xon = 1;xPos = 0;}
	    if (xPos >= (width - Woffset)) 
		    {xon = 0;xPos = (width - Woffset);   }
    }
	
	function start()
	{
	 	img1.display = "none";
		interval = setInterval('changePos()', delay);
	}
	function pause_resume() 
	{
		if(pause) 
		{
			clearInterval(interval);
			pause = false;
		}
		else 
		{
			interval = setInterval('changePos()',delay);
			pause = true; 
		}
	}
	start();
}