var intr = "";
          var array_key = 0;            /*start key in array of image id*/
          var images = new Array();
          var opacityInterval = 50;     /*milisec*/
          var opacityVal = 0.05;        /*step for opacity change*/
          var imgViewInterval = 1500;   /*milisec*/
          
          
          /*gel element id*/
          function getElem(id){         
               return document.getElementById(id);
          }
          
          /*gel element opacity*/
          function getOpacity(elem){
               return elem.style.opacity;
          }
          
          /*clear interval for timer*/
          function clearInt(){
               clearInterval(intr);
               intr = "";
          }
          
          /*set interval for call some function*/
          function timer(img_name){
               if(intr == ""){
                    intr = setInterval("setOpacity(getElem('"+img_name+"'))",opacityInterval);
               }
               else{clearInt();}
          }
          
          /*set element opacity*/
          function setOpacity(elem) {
               
               op = getOpacity(elem);
               
               if(op <= 0){     /*kontroluje průhlednost pokud je 0 a menší přeskočí na další obrázek*/
                    array_key++;
                    clearInt();
                    elem.style.display = 'none';
                    startPresentation();
               }
               
               else{
                    elem.style.opacity = op-opacityVal;
                    ieVal = (op*100)-5;
                    elem.style.filter = "alpha(opacity="+ieVal+")";
               }
          }
          
          /*controller when can be presentation started*/
          function startPresentation(){
               
               if(array_key+1 > images.length){
                    setStartParameters();
               }
               else{
                    
                    if(array_key+1 == images.length){setOpacityFirstImg();}
                    
                    img_name = images[array_key];
                    setTimeout("timer('"+img_name+"')",imgViewInterval);
               }
          }
          
          /*set values for first element at the end of loop*/
          function setOpacityFirstImg(){
               elem = getElem(images[0]);
               elem.style.opacity = 1;
               elem.style.zIndex = 0;
               elem.style.display = 'block';
               elem.style.filter = "alpha(opacity=100)";
          }
          
          /*set default values for all elements*/
          function setStartParameters(){
               
               
               zindex = images.length;
               
               for(var img in images){
                    
                    elem = getElem(images[img]);
                    
                    elem.style.display = 'block';
                    elem.style.zIndex = zindex;
                    elem.style.opacity = 1;
                    elem.style.filter = "alpha(opacity=100)";
                    zindex--;
               }
     
     
               array_key = 0;
               zindex = images.length;
               startPresentation();
          }
          
          /*add elements id from box*/
          function addId(){
               
               elem = getElem('introBox');
               x=elem.getElementsByTagName("img");
               for(var i=0; i <= (x.length-1); i++){
                    images[i] = x[i].id;
               }
               
          }