if (document.images) {            
            img1on = new Image();   img1on.src = "images/inb1a.gif"; 
            img2on = new Image();   img2on.src = "images/inb2a.gif"; 
            img3on = new Image();   img3on.src = "images/inb3a.gif"; 
            img4on = new Image();   img4on.src = "images/inb4a.gif"; 
            img5on = new Image();   img5on.src = "images/inb5a.gif"; 
            img6on = new Image();   img6on.src = "images/inb6a.gif"; 
            img7on = new Image();   img7on.src = "images/inb7a.gif"; 
            img8on = new Image();   img8on.src = "images/inb8a.gif"; 

            img9on = new Image();    img9on.src = "images/but1a.gif"; 
            img10on = new Image();   img10on.src = "images/but2a.gif"; 
            img11on = new Image();   img11on.src = "images/but3a.gif"; 
            img12on = new Image();   img12on.src = "images/but4a.gif"; 
            img13on = new Image();   img13on.src = "images/but5a.gif"; 
            img14on = new Image();   img14on.src = "images/but6a.gif"; 
            img15on = new Image();   img15on.src = "images/but7a.gif"; 
            img16on = new Image();   img16on.src = "images/but8a.gif"; 
            


            img1off = new Image();  img1off.src = "images/inb1.gif"; 
            img2off = new Image();  img2off.src = "images/inb2.gif"; 
            img3off = new Image();  img3off.src = "images/inb3.gif"; 
            img4off = new Image();  img4off.src = "images/inb4.gif"; 
            img5off = new Image();  img5off.src = "images/inb5.gif"; 
            img6off = new Image();  img6off.src = "images/inb6.gif"; 
            img7off = new Image();  img7off.src = "images/inb7.gif"; 
            img8off = new Image();  img8off.src = "images/inb8.gif"; 
 
            img9off = new Image();   img9off.src  = "images/but1.gif"; 
            img10off = new Image();  img10off.src = "images/but2.gif";
            img11off = new Image();  img11off.src = "images/but3.gif";
            img12off = new Image();  img12off.src = "images/but4.gif";
            img13off = new Image();  img13off.src = "images/but5.gif";
            img14off = new Image();  img14off.src = "images/but6.gif";
            img15off = new Image();  img15off.src = "images/but7.gif";
            img16off = new Image();  img16off.src = "images/but8.gif";

      }

    function imgOn(imgName) {
            if (document.images) {
                document[imgName].src = eval(imgName + "on.src");       
            }
    }

    function imgOff(imgName) {
            if (document.images) {
                document[imgName].src = eval(imgName + "off.src");        
            }
    }