var c = 1;

/* Preloading images */
var image1 = new Image();
image1.src = "a1.jpg";
var image2 = new Image();
image2.src = "a2.jpg";
var image3 = new Image();
image3.src = "a3.jpg";
var image4 = new Image();
image4.src = "a4.jpg";
var image5 = new Image();
image5.src = "a5.jpg";
var image6 = new Image();
image6.src = "a6.jpg";
var image7 = new Image();
image7.src = "a7.jpg";
var image8 = new Image();
image8.src = "a8.jpg";

function disp_img(w)
   {
   if (c == 9)
      {
      c = 1;
      }
   var img_src = "a" + c + ".jpg";
   document.ani.src = img_src;
   c++;
   }
t = setInterval("disp_img(c)", 2500);