var version = false;

	if ((navigator.userAgent.substring(0,9) == "Mozilla/4") || (navigator.userAgent.substring(0,9) == "Mozilla/3") )
        {
		version = true;

		bildon = new Image();
		bildon.src = "grafik/button-on.gif";
		bildoff = new Image()
		bildoff.src = "grafik/button-off.gif"
        }

	var geklickt = null


	function on(i)
        {
                //if (navigator.userAgent.substring(0,9) == "Mozilla/4")
                if (version == true)
                {
                if (geklickt != i)
                document.images[i].src=bildon.src
                }
        }

	function off(i)
        
        {
                //if (navigator.userAgent.substring(0,9) == "Mozilla/4")
                if (version == true)
                {
                if (geklickt != i)
                document.images[i].src = bildoff.src
                }
        }