var c = 1;

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";

function disp_img(w)
	{
	if (c == 6)
		{
		c = 1;
		}
	var img_src = "a" + c + ".jpg";
	document.ani.src = img_src;
	c++;
	}

t = setInterval("disp_img(c)", 1000);