var loadingImage = 'loading.gif';
var closeButton = 'close.gif';              

function getPageScroll(){

       var yScroll;

       if (self.pageYOffset) {
              yScroll = self.pageYOffset;
       } else if (document.documentElement && document.documentElement.scrollTop){        
              yScroll = document.documentElement.scrollTop;
       } else if (document.body) {
              yScroll = document.body.scrollTop;
       }

       arrayPageScroll = new Array('',yScroll) 
       return arrayPageScroll;
}

function getPageSize(){
       
       var xScroll, yScroll;
       
       if (window.innerHeight && window.scrollMaxY) {       
              xScroll = document.body.scrollWidth;
              yScroll = window.innerHeight + window.scrollMaxY;
       } else if (document.body.scrollHeight > document.body.offsetHeight){ 
              xScroll = document.body.scrollWidth;
              yScroll = document.body.scrollHeight;
       } else { 
              xScroll = document.body.offsetWidth;
              yScroll = document.body.offsetHeight;
       }
       
       var windowWidth, windowHeight;
       if (self.innerHeight) {     
              windowWidth = self.innerWidth;
              windowHeight = self.innerHeight;
       } else if (document.documentElement && document.documentElement.clientHeight) { 
              windowWidth = document.documentElement.clientWidth;
              windowHeight = document.documentElement.clientHeight;
       } else if (document.body) { 
              windowWidth = document.body.clientWidth;
              windowHeight = document.body.clientHeight;
       }       
       
       
       if(yScroll < windowHeight){
              pageHeight = windowHeight;
       } else { 
              pageHeight = yScroll;
       }

      
       if(xScroll < windowWidth){       
              pageWidth = windowWidth;
       } else {
              pageWidth = xScroll;
       }


       arrayPageSize = new Array(pageWidth,pageHeight,windowWidth,windowHeight) 
       return arrayPageSize;
}



function pause(numberMillis) {
       var now = new Date();
       var exitTime = now.getTime() + numberMillis;
       while (true) {
              now = new Date();
              if (now.getTime() > exitTime)
                     return;
       }
}



function getKey(e){
       if (e == null) { 
              keycode = event.keyCode;
       } else { 
              keycode = e.which;
       }
       key = String.fromCharCode(keycode).toLowerCase();
       
       if(key == 'x'){ hideLightbox(); }
}



function listenKey () {       document.onkeypress = getKey; }
       


function showLightbox(objLink)
{
      
       var objOverlay = document.getElementById('overlay');
       var objLightbox = document.getElementById('lightbox');
       var objCaption = document.getElementById('lightboxCaption');
       var objImage = document.getElementById('lightboxImage');
       var objLoadingImage = document.getElementById('loadingImage');
       var objLightboxDetails = document.getElementById('lightboxDetails');

       
       var arrayPageSize = getPageSize();
       var arrayPageScroll = getPageScroll();

       
       if (objLoadingImage) {
              objLoadingImage.style.top = (arrayPageScroll[1] + ((arrayPageSize[3] - 35 - objLoadingImage.height) / 2) + 'px');
              objLoadingImage.style.left = (((arrayPageSize[0] - 20 - objLoadingImage.width) / 2) + 'px');
              objLoadingImage.style.display = 'block';
       }

      
       objOverlay.style.height = (arrayPageSize[1] + 'px');
       objOverlay.style.display = 'block';

       
       imgPreload = new Image();

       imgPreload.onload=function(){
              objImage.src = objLink.href;

              
              var lightboxTop = arrayPageScroll[1] + ((arrayPageSize[3] - 35 - imgPreload.height) / 2);
              var lightboxLeft = ((arrayPageSize[0] - 20 - imgPreload.width) / 2);
              
              objLightbox.style.top = (lightboxTop < 0) ? "0px" : lightboxTop + "px";
              objLightbox.style.left = (lightboxLeft < 0) ? "0px" : lightboxLeft + "px";


              objLightboxDetails.style.width = imgPreload.width + 'px';
              
              if(objLink.getAttribute('title')){
                     objCaption.style.display = 'block';
                     
                     objCaption.innerHTML = objLink.getAttribute('title');
              } else {
                     objCaption.style.display = 'none';
              }
              
              
              if (navigator.appVersion.indexOf("MSIE")!=-1){
                     pause(250);
              } 

              if (objLoadingImage) {       objLoadingImage.style.display = 'none'; }

              
              selects = document.getElementsByTagName("select");
        for (i = 0; i != selects.length; i++) {
                selects[i].style.visibility = "hidden";
        }

       
              objLightbox.style.display = 'block';

              
              arrayPageSize = getPageSize();
              objOverlay.style.height = (arrayPageSize[1] + 'px');
              
             
              listenKey();

              return false;
       }

       imgPreload.src = objLink.href;
       
}


function hideLightbox()
{
       
       objOverlay = document.getElementById('overlay');
       objLightbox = document.getElementById('lightbox');

       
       objOverlay.style.display = 'none';
       objLightbox.style.display = 'none';

      
       selects = document.getElementsByTagName("select");
    for (i = 0; i != selects.length; i++) {
              selects[i].style.visibility = "visible";
       }

      
       document.onkeypress = '';
}





function initLightbox()
{
       
       if (!document.getElementsByTagName){ return; }
       var anchors = document.getElementsByTagName("a");

      
       for (var i=0; i<anchors.length; i++){
              var anchor = anchors[i];

              if (anchor.getAttribute("href") && (anchor.getAttribute("rel") == "lightbox")){
                     anchor.onclick = function () {showLightbox(this); return false;}
              }
       }

      
       var objBody = document.getElementsByTagName("body").item(0);
       
       
       var objOverlay = document.createElement("div");
       objOverlay.setAttribute('id','overlay');
       objOverlay.onclick = function () {hideLightbox(); return false;}
       objOverlay.style.display = 'none';
       objOverlay.style.position = 'absolute';
       objOverlay.style.top = '0';
       objOverlay.style.left = '0';
       objOverlay.style.zIndex = '90';
        objOverlay.style.width = '100%';
       objBody.insertBefore(objOverlay, objBody.firstChild);
       
       var arrayPageSize = getPageSize();
       var arrayPageScroll = getPageScroll();

      
       var imgPreloader = new Image();
       
       
       imgPreloader.onload=function(){

              var objLoadingImageLink = document.createElement("a");
              objLoadingImageLink.setAttribute('href','#');
              objLoadingImageLink.onclick = function () {hideLightbox(); return false;}
              objOverlay.appendChild(objLoadingImageLink);
              
              var objLoadingImage = document.createElement("img");
              objLoadingImage.src = loadingImage;
              objLoadingImage.setAttribute('id','loadingImage');
              objLoadingImage.style.position = 'absolute';
              objLoadingImage.style.zIndex = '150';
              objLoadingImageLink.appendChild(objLoadingImage);

              imgPreloader.onload=function(){};       

              return false;
       }

       imgPreloader.src = loadingImage;

      
       var objLightbox = document.createElement("div");
       objLightbox.setAttribute('id','lightbox');
       objLightbox.style.display = 'none';
       objLightbox.style.position = 'absolute';
       objLightbox.style.zIndex = '100';       
       objBody.insertBefore(objLightbox, objOverlay.nextSibling);
       
       
       var objLink = document.createElement("a");
       objLink.setAttribute('href','#');
       objLink.setAttribute('title','Click to close');
       objLink.onclick = function () {hideLightbox(); return false;}
       objLightbox.appendChild(objLink);

       
       var imgPreloadCloseButton = new Image();

      
       imgPreloadCloseButton.onload=function(){

              var objCloseButton = document.createElement("img");
              objCloseButton.src = closeButton;
              objCloseButton.setAttribute('id','closeButton');
              objCloseButton.style.position = 'absolute';
              objCloseButton.style.zIndex = '200';
              objLink.appendChild(objCloseButton);

              return false;
       }

       imgPreloadCloseButton.src = closeButton;

       
       var objImage = document.createElement("img");
       objImage.setAttribute('id','lightboxImage');
       objLink.appendChild(objImage);
       
       
       var objLightboxDetails = document.createElement("div");
       objLightboxDetails.setAttribute('id','lightboxDetails');
       objLightbox.appendChild(objLightboxDetails);

       
       var objCaption = document.createElement("div");
       objCaption.setAttribute('id','lightboxCaption');
       objCaption.style.display = 'none';
       objLightboxDetails.appendChild(objCaption);

       
       var objKeyboardMsg = document.createElement("div");
       objKeyboardMsg.setAttribute('id','keyboardMsg');
       objKeyboardMsg.innerHTML = 'press <a href="#" onclick="hideLightbox(); return false;"><kbd>x</kbd></a> to close';
       objLightboxDetails.appendChild(objKeyboardMsg);


}





function addLoadEvent(func)
{       
       var oldonload = window.onload;
       if (typeof window.onload != 'function'){
           window.onload = func;
       } else {
              window.onload = function(){
              oldonload();
              func();
              }
       }

}



addLoadEvent(initLightbox);