function swap_img(name, imgfile) {
  var img = eval((navigator.appName.indexOf('Netscape', 0) != -1) ? 'document.'+name : 'document.all.'+name);
  if (name == '') return;
  if (img) {
	img.altsrc = img.src;
	img.src    = imgfile;
  }
}

function restore_img(name) {
  var img = eval((navigator.appName.indexOf('Netscape', 0) != -1) ? 'document.'+name : 'document.all.'+name);
  if (name == '') return;
  if (img && img.altsrc) {
	img.src    = img.altsrc;
	img.altsrc = null;
  }
}