var isMinNS4 = (navigator.appName.indexOf("Netscape") >= 0 &&
                parseFloat(navigator.appVersion) >= 4) ? 1 : 0;
var isMinIE4 = (document.all) ? 1 : 0;
var isMinIE5 = (isMinIE4 && navigator.appVersion.indexOf("5.")) >= 0 ? 1 : 0;

function hideLayer(layer) {

  if (isMinNS4)
    layer.visibility = "hide";
  if (isMinIE4)
    layer.style.visibility = "hidden";
}

function showLayer(layer) {

  if (isMinNS4)
    layer.visibility = "show";
  if (isMinIE4)
    layer.style.visibility = "visible";
}

function moveLayerTo(layer, x, y) {

  if (isMinNS4)
    layer.moveTo(x, y);
  if (isMinIE4) {
    layer.style.left = x;
    layer.style.top  = y;
  }
}

function clipLayer(layer, clipleft, cliptop, clipright, clipbottom) {

  if (isMinNS4) {
    layer.clip.left   = clipleft;
    layer.clip.top    = cliptop;
    layer.clip.right  = clipright;
    layer.clip.bottom = clipbottom;
  }
  if (isMinIE4)
    layer.style.clip = 'rect(' + cliptop + ' ' +  clipright + ' ' + clipbottom + ' ' + clipleft +')';
}

function getHeight(layer) {

  if (isMinNS4) {
    if (layer.document.height)
      return(layer.document.height);
    else
      return(layer.clip.bottom - layer.clip.top);
  }
  if (isMinIE4) {
    if (false && layer.style.pixelHeight)
      return(layer.style.pixelHeight);
    else
      return(layer.clientHeight);
  }
  return(-1);
}

function getLayer(name) {

  if (isMinNS4)
    return findLayer(name, document);
  if (isMinIE4)
    return eval('document.all.' + name);

  return null;
}

function findLayer(name, doc) {

  var i, layer;

  for (i = 0; i < doc.layers.length; i++) {
    layer = doc.layers[i];
    if (layer.name == name)
      return layer;
    if (layer.document.layers.length > 0) {
      layer = findLayer(name, layer.document);
      if (layer != null)
        return layer;
    }
  }

  return null;
}

function getWindowWidth() {

  if (isMinNS4)
    return(window.innerWidth);
  if (isMinIE4)
    return(document.body.clientWidth);
  return(-1);
}

function getWindowHeight() {

  if (isMinNS4)
    return(window.innerHeight);
  if (isMinIE4)
    return(document.body.clientHeight);
  return(-1);
}

function getPageScrollX() {

  if (isMinNS4)
    return(window.pageXOffset);
  if (isMinIE4)
    return(document.body.scrollLeft);
  return(-1);
}

function getPageScrollY() {

  if (isMinNS4)
    return(window.pageYOffset);
  if (isMinIE4)
    return(document.body.scrollTop);
  return(-1);
}

function getPageWidth() {

  if (isMinNS4)
    return(document.width);
  if (isMinIE4)
    return(document.body.scrollWidth);
  return(-1);
}

function getPageHeight() {

  if (isMinNS4)
    return(document.height);
  if (isMinIE4)
    return(document.body.scrollHeight);
  return(-1);
}

function setBgColor(layer, color) {
  if (isMinNS4) layer.bgColor               = color;
  if (isMinIE4) layer.style.backgroundColor = color;
}