var prevLink = null;
            
            function setActive(objLink) {
                if(prevLink != null){
                    prevLink.parentNode.className = "";
                }

                objLink.parentNode.className = "Active";
                prevLink = objLink;
            }
            
            
            function restore(){
                 prevLink.parentNode.className = "";
                 prevLink = null;
            }
            
            window.onload = function(){
                var objNav;
                var colNavs = new Array(
                        document.getElementById("NavigationPro"),
                        document.getElementById("NavigationPers")
                );
                
                for(var x = 0;x < colNavs.length;x++){
                    colLinks = colNavs[x].getElementsByTagName("a");
                   
                    for(var i = 0;i < colLinks.length;i++){
                        colLinks[i].onclick = function(){
                            setActive(this);
                        }
                    }
                }
                
                var objImgs = new Array(
                    "images/ubot/content_UBot_01.jpg",
  "images/ubot/content_UBot_02.jpg", "images/tunnels/content_Tunnels_01.jpg",
 "images/tunnels/content_Tunnels_01_1.jpg",
 "images/sacred2/content_Sacred2_01.jpg",
                    "images/dwiii/content_DWIII_01.jpg",
                    "images/rbr/content_RBR_01.jpg",
                    "images/env/content_Env_01.jpg",
                    "images/scrap/content_Scrap_01.jpg",
                    "images/madmax/content_MadMaxProps_01.jpg"
                );
                // preload of main images
                var image;
                
                for(var i = 0;i < objImgs.length;i++){
                    image = new Image();
                    image.src = objImgs[i];
                }
            }