var imageArray = new Array();

/**
 * 
 * 
 * @return
 */
function hideLayer() {
 window.document.getElementById('layerFrame').className = 'lmLayerHide';
 window.document.getElementById('layerImage').src = '';
 window.document.getElementById('layerImageFrame').className = 'layerImageFrameHide';
}
/**
 * 
 * 
 * @param imgUrl
 * @return
 */
function showImageInLayer(imgUrl, index) {
 
 imgCount = imageArray.length;
 
 var indexBack = index-1;
 var indexForward = index+1;
 
 if (indexBack < 0) {
  indexBack = imgCount-1;
 }
 if (indexForward >= imgCount) {
  indexForward = 0;
 }
 
 window.document.getElementById('layerFrame').className = 'lmLayerDisplay';
 window.document.getElementById('layerImage').src = imgUrl;
 window.document.getElementById('layerImageFrame').className = 'layerImageFrameDisplay';
 
 if (index === 0) {
  // no event, hide button
  window.document.getElementById('layerImageBack').onclick =  function() {};
  window.document.getElementById('layerImageBack').className = 'layerImageBackHide';
 } else {
  window.document.getElementById('layerImageBack').onclick =  function() {showImageInLayer(imageArray[indexBack], indexBack)};
  window.document.getElementById('layerImageBack').className = 'layerImageBack';
 }
 
 if (index === (imgCount-1)) {
  window.document.getElementById('layerImageForward').onclick =  function() {};
  window.document.getElementById('layerImageForward').className = 'layerImageForwardHide';
 } else {
  window.document.getElementById('layerImageForward').onclick =  function() {showImageInLayer(imageArray[indexForward], indexForward)};
  window.document.getElementById('layerImageForward').className = 'layerImageForward';
 }
	 
}