var xPos = 20;
            var yPos = document.body.clientHeight;
            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 img = document.getElementById("flyimg");
			if(img!=null) 
			{
                img.style.top = yPos;
			}
			
            function changePos() 
            {
                width = document.body.clientWidth;
                height = document.body.clientHeight;
                Hoffset = img.offsetHeight;
                Woffset = img.offsetWidth;
               
                img.style.left = xPos + document.body.scrollLeft;
                img.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() {
                img.visibility = "visible";
                interval = setInterval('changePos()', delay);
            }

            start();