if (document.images)
{	var next = new Image();
	next.src = "next1.gif";
	var next_a = new Image();
	next_a.src = "next2.gif";
    var back = new Image();
    back.src = "back1.gif";
    var back_a = new Image();
    back_a.src = "back2.gif";
}

function inact(imgName)
{   if (document.images)
	document[imgName].src = eval(imgName + '.src');
}

function act(imgName)
{   if (document.images)
	document[imgName].src = eval(imgName + '_a.src');
}