var isMinNS4 = (document.layers) ? 1 : 0;
var isMinIE4 = (document.all)    ? 1 : 0;
var isMinNS6 = (document.getElementById && !isMinIE4) ? 1 : 0;
var linkAt = 1;

function hideLayer(layer) {
    if (isMinNS6)
     layer.style.visibility = "hidden";
   else if (isMinNS4)
     layer.visibility = "hide";
   else if (isMinIE4)
     layer.style.visibility = "hidden";
}

function showLayer(layer) {
  if ( isMinNS6)
    layer.style.visibility = "visible";
  else  if (isMinNS4)
    layer.visibility = "show";
  else if (isMinIE4)
    layer.style.visibility = "visible";
}

function getLayer(layername) {
  if (isMinNS6)
      layer = document.getElementById(layername); 
  else  if (isMinNS4) 
      layer = document.layers[layername]; 
  else if (isMinIE4) 
      layer = eval('document.all.' + layername);
  return layer;
}

function updateSelection() {
     if (doBigOrb == true)  {
        highliteDiv('link'+linkAt);
        return;
     }
    if ( isMinNS6) {
      layer = document.getElementById('link'+linkAt+'div'); 
      layer.style.color = selectColor;
      layer = document.getElementById('labelSpan'); 
    }
    else  if (isMinNS4) {
      layer = document.layers['link'+linkAt+'div']; 
      layer.color = selectColor;
      layer = document.layers['labelSpan']; 
    }
    else if (isMinIE4)  {
       layer = document.getElementById('link'+linkAt+'div'); 
       layer.style.color = selectColor;
       layer = document.getElementById('labelSpan'); 
    }
    layer.innerHTML = orbText[linkAt];
}

function clearSelection() {
     if (doBigOrb == true)  {
        unliteDiv('link'+linkAt);
        return;
     }
    if ( isMinNS6) {
      layer = document.getElementById('link'+linkAt+'div'); 
      layer.style.color = clearSelColor;
    }
    else  if (isMinNS4) {
      layer = document.layers['link'+linkAt+'div']; 
      layer.color = clearSelColor;
     }
    else if (isMinIE4) {
      layer = document.getElementById('link'+linkAt+'div'); 
      layer.style.color = clearSelColor;
    }
}

// for big orb pictures
function highliteDiv(layername) {
  unliteDiv('link'+linkAt);
  linkAt = parseInt(layername.substring(4,5));
//  window.status = "link at "+linkAt;
  if ( isMinNS6) {
    layer = document.getElementById(layername+'div'); 
    layer.style.border = selectBorder;
    layer.style.zIndex = 4;
  }
  else  if (isMinNS4) {
    layer = document.layers[layername+'div']; 
    layer.border = selectBorder;
    layer.zIndex = 4;
   }
  else if (isMinIE4) {
    layer = eval('document.all.' + layername+'div');
    layer.style.border = selectBorder;
    layer.style.zIndex = 4;
  }
  
  if (doBigOrb == true)  {
        layer = getLayer('palantirImg');
        layer.src = orbImages[linkAt];
        var newImg = new Image();
        newImg.src = orbImages[linkAt];
        var height = newImg.height;
        var width = newImg.width;
  window.status = "link at "+linkAt +"  img: "+orbImages[linkAt]+"  width "+width+"  ht "+height;
        var newleft = 630 - (width/2);
        var newtop = 400 - (height/2);
        layer.style.top = newtop +'px'
        layer.style.left = newleft +'px'
        return;
   }
}

function unliteDiv(layername) {
  if ( isMinNS6) {
    layer = document.getElementById(layername+'div'); 
    layer.style.border = clearSelBorder;
    layer.style.zIndex = 4;
  }
  else  if (isMinNS4) {
    layer = document.layers[layername+'div']; 
    layer.border = clearSelBorder;
    layer.zIndex = 4;
   }
  else if (isMinIE4) {
    layer = eval('document.all.' + layername+'div');
    layer.style.border = clearSelBorder;
    layer.style.zIndex = 4;
  }
}

function setImg(layer, imgname) {
    layer.src=imgname;
}

function gotoPage() {
    window.location= linkLocs[linkAt]; 
}

function setLinkAt(linkat) {
    clearSelection();
	linkAt = linkat;
	window.status = "link at "+linkAt;
    updateSelection();
}

function hookEvent(element, eventName, callback)  {
  if(typeof(element) == "string")
    element = document.getElementById(element);
  if(element == null)
    return;
  if(element.addEventListener)  {
    if(eventName == 'mousewheel')
      element.addEventListener('DOMMouseScroll', callback, false);  
    element.addEventListener(eventName, callback, false);
  }
  else if(element.attachEvent)
    element.attachEvent("on" + eventName, callback);
}

function unhookEvent(element, eventName, callback)  {
  if(typeof(element) == "string")
    element = document.getElementById(element);
  if(element == null)
    return;
  if(element.removeEventListener)  {
    if(eventName == 'mousewheel')
      element.removeEventListener('DOMMouseScroll', callback, false);  
    element.removeEventListener(eventName, callback, false);
  }
  else if(element.detachEvent)
    element.detachEvent("on" + eventName, callback);
}

function MouseWheel(e)  {
  e = e ? e : window.event;
  var delta = e.detail ? e.detail * -1 : e.wheelDelta / 40;
  //do something
    clearSelection();
	if (delta < 0) {
		linkAt = linkAt + 1;
        if (linkAt > nlinks) linkAt = 1;
	}
	else  {
        linkAt = linkAt - 1;
        if (linkAt <= 0) linkAt = nlinks;
	}
    updateSelection('link'+linkAt);
 // return cancelEvent(e);
}