versOk = ( ((navigator.appName == "Netscape")&& 
            (parseInt(navigator.appVersion) >= 3)) ||
        
           ((navigator.appName == "Microsoft Internet Explorer")&&
            (parseInt(navigator.appVersion)>=4))
          );
if (versOk) 
{		
  
  a1 = new Image();     a1.src ="img/g1a.jpg"
  a2 = new Image();     a2.src ="img/g1.jpg"
  b1 = new Image();     b1.src ="img/g5a.jpg"
  b2 = new Image();     b2.src ="img/g5.jpg"
  c1 = new Image();     c1.src ="img/g2a.jpg"
  c2 = new Image();     c2.src ="img/g2.jpg"
    d1 = new Image();		d1.src ="img/g7a.jpg"
 d2 = new Image();		d2.src ="img/g7.jpg"
  e1 = new Image();     e1.src ="img/g12a.jpg"
  e2 = new Image();     e2.src ="img/g12.jpg"
  f1 = new Image();     f1.src ="img/g4a.jpg"
  f2 = new Image();     f2.src ="img/g4.jpg"
 g1 = new Image();     g1.src ="img/g9a.jpg"
  g2 = new Image();     g2.src ="img/g9.jpg"

  h1 = new Image();     h1.src ="img/g3a.jpg"
  h2 = new Image();     h2.src ="img/g3.jpg"
  i1 = new Image();     i1.src ="img/g6a.jpg"
  i2 = new Image();     i2.src ="img/g6.jpg"
   j1 = new Image();     j1.src ="img/g13a.jpg"
  j2 = new Image();     j2.src ="img/g13.jpg"
   k1 = new Image();     k1.src ="img/g15.jpg"
  k2 = new Image();     k2.src ="img/g15a.jpg"
  l1 = new Image();     l1.src ="img/g14a.jpg"
  l2 = new Image();     l2.src ="img/g14.jpg"
  
}


function rollOn(n)
{
 if (versOk)
        {
           light=eval(n+"2.src");
           document [n].src=light;
        }
}

function rollOff(n)
{
 if (versOk)
        {
           dark=eval(n+"1.src");
           document [n].src=dark;
        }
}