function RandomNumber()
{
  var today = new Date();
  var num= Math.abs(Math.sin(today.getTime()/1000));
  return num;
}

function RandomGraphics() 
{
  var x = RandomNumber();

  if (x > .50) 
{document.write("<object classid='clsid:D27CDB6E-AE6D-11cf-96B8-444553540000' codebase='http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=7,0,19,0' width='468' height='60'><param name='movie' value='http://www.marcasur.com/es/fotos/image/banners/banner_largo.swf' /><param name='quality' value='high' /><embed src='http://www.marcasur.com/es/fotos/image/banners/banner_largo.swf quality='high' pluginspage='http://www.macromedia.com/go/getflashplayer' type='application/x-shockwave-flash' width='468' height='60'></embed></object>"); return; 
}
  if (x > 0)   
{document.write("<a href=http://www.marcasur.com/es/novedades.asp><img src=http://www.marcasur.com/es/fotos/image/banners/noticiasmarcasur.gif border=0 ></a>"); return; 
}
}
RandomGraphics();