var swImg = new Array;

function PreloadImg()
{
  var appVer = parseInt(navigator.appVersion);
  var isNC = false;
  var isN6 = false;
  var isIE = false;

  if (document.all && appVer >= 4)
  {
    isIE = true;
  }
  else if (document.getElementById && appVer > 4)
  {
    isN6 = true;
  }
  else if (document.layers && appVer >= 4)
  {
    isNC = true;
  }

  if (isNC || isN6 || isIE)
  {
    if (document.images)
    {
      var imgName = PreloadImg.arguments[0];

      swImg[imgName] = new Array;

      for (var i = 1; i < PreloadImg.arguments.length; i++)
      {
        swImg[imgName][PreloadImg.arguments[i]] = new Image();
        swImg[imgName][PreloadImg.arguments[i]].src = PreloadImg.arguments[i];
      }
    }
  }
}

function FindImg(doc, imgName)
{
  for (var i = 0; i < doc.layers.length; i++)
  {
    var img = doc.layers[i].document.images[imgName];

    if (!img)
    {
      img = FindImg(doc.layers[i], imgName);
    }

    if (img) 
    {
      return img;
    }
  }

  return null;
}

function SwapImg(imgName, imgSrc)
{
  var appVer = parseInt(navigator.appVersion);
  var isNC = false;
  var isN6 = false;
  var isIE = false;

  if (document.all && appVer >= 4)
  {
    isIE = true;
  }
  else if (document.getElementById && appVer > 4)
  {
    isN6 = true;
  }
  else if (document.layers && appVer >= 4)
  {
    isNC = true;
  }

  if (isNC || isN6 || isIE)
  {
    if (document.images)
    {
      var img = document.images[imgName];

      if (!img) img = FindImg(document, imgName);
      if (img) img.src = imgSrc;
    }
  }
}

function SwapImgButton(btnName, imgSrc)
{
  var appVer = parseInt(navigator.appVersion);
  var isNC = false;
  var isN6 = false;
  var isIE = false;

  if (document.all && appVer >= 4)
  {
    document.all[btnName].src = imgSrc;
  }
  else if (document.getElementById && appVer > 4)
  {
    document.getElementById[btnName].src = imgSrc;
  }
  else if (document.layers && appVer >= 4)
  {
    document.layers[btnName].src = imgSrc;
  }
}