var xPos2 = 500;
var yPos2 = 500; 
var step2 = 1;
var delay2= 20; 
var height2 = 0;
var Hoffset2 = 0;
var Woffset2 = 0;
var yon2 = 0;
var xon2 = 0;
var pause2 = true;
var interval2;
img2.style.top = yPos2;
function changePos2() 
{
width2 = document.body.clientWidth;
height2 = document.body.clientHeight;
Hoffset2 = img2.offsetHeight;
Woffset2 = img2.offsetWidth;
img2.style.left = xPos2 + document.body.scrollLeft;
img2.style.top = yPos2 + document.body.scrollTop;
if (yon2) 
{yPos2 = yPos2 + step2;}
else 
{yPos2 = yPos2 - step2;}
if (yPos2 < 0) 
{yon2 = 1;yPos2 = 0;}
if (yPos2 >= (height2 - Hoffset2)) 
{yon2 = 0;yPos2 = (height2 - Hoffset2);}
if (xon2) 
{xPos2 = xPos2 + step2;}
else 
{xPos2 = xPos2 - step2;}
if (xPos2 < 0) 
{xon2 = 1;xPos2 = 0;}
if (xPos2 >= (width2 - Woffset2)) 
{xon2 = 0;xPos2 = (width2 - Woffset2);   }
}

function start2()
{
img2.visibility = "visible";
interval2 = setInterval('changePos2()', delay2);
}
function pause_resume2() 
{
if(pause2) 
{
clearInterval(interval2);
pause2 = false;}
else 
{
interval2 = setInterval('changePos2()',delay2);
pause2 = true; 
}
}
start2();