var box = 7;			// ### NO OF ANIMATION BOXES
var opacStart = 40;		// ### OPACITY lower
var opacEnd = 70;		// ### OPACITY upper
var loop = 125;			// ### change speed
var shade = opacStart;	// ### OPACITY init

var b = 0; var bb = 0 	// ### box loop init
function headtrack() {
	b++; if (b > box) { b = 1 };
	opacity("img" + b);
	setTimeout("headtrack()",loop);
}

function opacity(id) {
if (shade > opacStart)
			{shade = opacStart}
else  {shade = opacEnd}

	var object = document.getElementById(id).style;
	object.opacity = (shade / 100);
	object.MozOpacity = (shade / 100);
	object.KhtmlOpacity = (shade / 100);
	object.filter = "alpha(opacity=" + shade + ")";
}