fValidVer = 
   (((navigator.appName == "Netscape") && 
   (parseInt(navigator.appVersion) >= 3 )) || 
   ((navigator.appName == "Microsoft Internet Explorer") && 
   (parseInt(navigator.appVersion) >= 4 )));
  if (document.images){
   <!--BUTTONS-->
   var top_normal = new Image;
   top_normal.src = "Images/button_top_normal.jpg";
   var top_hover = new Image;
   top_hover.src = "Images/button_top_hover.jpg";
   var PictureNames = new Array(
   "Images/showiris1.jpg" ,
   "Images/showiris2.jpg" ,
   "Images/showiris3.jpg" ,
   "Images/showiris4.jpg" ,
   "Images/showiris5.jpg" ,
   "Images/showiris6.jpg" ,
   "Images/showiris7.jpg" ,
   "Images/showiris8.jpg" ,
   "Images/showiris9.jpg" ,
   "Images/showiris10.jpg" ,
   "Images/showiris11.jpg" ,
   "Images/showiris12.jpg" );
   var CurrentPic = 0;  //the counter for the image array
   var PriorPic = 11;  //the last cell in our array = (number of pictures - 1)
   Pictures=new Array(PriorPic);
   for(var counter=0;counter<=PriorPic;counter++){
    Pictures[counter] = new Image();
    Pictures[counter].src=PictureNames[counter];
   }
  }

  function Swap(image1, image2) {
   if (document.images)
   	document.images[image1].src = eval(image2 + ".src");
  }

  function processPrevious() {
   if (document.images) {
    if (CurrentPic==0) //if at the very beginning of array
    {
    CurrentPic=PriorPic; //goto the last cell in the array
    }
    else 
    {
    CurrentPic--; //else simply decrement the counter                    
    }
    document.Trees.src=Pictures[CurrentPic].src;
   }
  }

  function processNext() {
   if (document.images) {
    if (CurrentPic==PriorPic) //if at the very end of the array
    {
    CurrentPic=0; //goto the first cell of the array
    }
    else 
    {
    CurrentPic++; //else simply increment the counter
    }
    document.Trees.src=Pictures[CurrentPic].src;
   }
  }