if(document.images) {
  var imgs = new Array();
  imgs[0] = new Image();  imgs[0].src = "../b/1_out.gif"; //
  imgs[1] = new Image();  imgs[1].src = "../b/1_on.gif";
  imgs[2] = new Image();  imgs[2].src = "../b/2_out.gif";
  imgs[3] = new Image();  imgs[3].src = "../b/2_on.gif";
  imgs[4] = new Image();  imgs[4].src = "../b/3_out.gif";
  imgs[5] = new Image();  imgs[5].src = "../b/3_on.gif";
  imgs[6] = new Image();  imgs[6].src = "../b/4_out.gif";
  imgs[7] = new Image();  imgs[7].src = "../b/4_on.gif";
  imgs[8] = new Image();  imgs[8].src = "../b/5_out.gif";
  imgs[9] = new Image();  imgs[9].src = "../b/5_on.gif";
  imgs[10] = new Image();  imgs[10].src = "../b/6_out.gif";
  imgs[11] = new Image();  imgs[11].src = "../b/6_on.gif";
}

function chgimg(id, imgname) {
  if(document.images) {
   if(imgs[imgname]) {
     document.images[id].src = imgs[imgname].src;
   }
   else {
     document.images[id].src = imgname;
   }
  }
}