var xPos = 20;
var yPos = document.body.clientHeight;
var step = 1;
var delay = 5; 
var height = 0;
var Hoffset = 0;
var Woffset = 0;
var yon = 0;
var xon = 0;
var pause = true;
var interval;
if (document.getElementById("logo")) document.getElementById("logo").style.top = yPos;

function changePos() 
	{
	width = document.body.clientWidth;
	height = document.body.clientHeight;
	Hoffset = document.getElementById("logo").offsetHeight;
	Woffset = document.getElementById("logo").offsetWidth;
	document.getElementById("logo").style.left = xPos + document.body.scrollLeft;
	document.getElementById("logo").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);
		document.getElementById("logo").style.zIndex=-document.getElementById("logo").style.zIndex;
		}
	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() 
	{
	document.getElementById("logo").visibility = "visible";
	interval = setInterval('changePos()', delay);
	}

function pause_resume() 
	{
	if(pause) 
		{
		clearInterval(interval);
		pause = false;
		}
	else 
		{
		interval = setInterval('changePos()',delay);
		pause = true;
	   }
	}
//start();