function namosw_exchange_src() 
{ 
  str = namosw_exchange_src.arguments[0];
  str = (navigator.appName == 'Netscape') ? 'document.' + str : 'document.all.' + str;
  img = eval(str);
  if (img) {
    if (img.ori_src == null) {
      img.ori_src = img.src;
      img.src     = namosw_exchange_src.arguments[1];
    } else {
      var temp    = img.src;
      img.src     = img.ori_src;
      img.ori_src = temp;
    }
  } 
}

function na_change_img_src(name, nsdoc, rpath, preload)
{ 
  var img = eval((navigator.appName == 'Netscape') ? nsdoc+'.'+name : 'document.all.'+name);
  if (name == '')
    return;
  if (img) {
    img.altsrc = img.src;
    img.src    = rpath;
  } 
}

function na_restore_img_src(name, nsdoc)
{
  var img = eval((navigator.appName == 'Netscape') ? nsdoc+'.'+name : 'document.all.'+name);
  if (name == '')
    return;
  if (img && img.altsrc) {
    img.src    = img.altsrc;
    img.altsrc = null;
  } 
}