var image='http://i82.servimg.com/u/f82/11/82/98/47/routee10.jpg';
if(screen.width<=800) image= 'http://i82.servimg.com/u/f82/11/82/98/47/route_10.gif';
else if(screen.width<=1024) image= 'http://i82.servimg.com/u/f82/11/82/98/47/route_11.gif';
else if(screen.width<=1280) image= 'http://i82.servimg.com/u/f82/11/82/98/47/route_12.jpg';
else if(screen.width<=1440) image='http://i82.servimg.com/u/f82/11/82/98/47/route_13.jpg';
else if(screen.width<=1600) image='http://i82.servimg.com/u/f82/11/82/98/47/routee10.jpg';
document.body.style.background='url('+image+')';
document.body.style.backgroundAttachment = "fixed";