browser = (((navigator.appName == "Netscape") &&
(parseInt(navigator.appVersion) >= 3 )) || ((navigator.appName ==
"Microsoft Internet Explorer") && (parseInt(navigator.appVersion) >= 4 )))

        
        if (browser) {
        toc1on = new Image(25, 25);
        toc1on.src = "images/butt_mute_h.gif";
        toc2on = new Image(25, 25);
        toc2on.src = "images/butt_riattacca_h.gif";
	toc3on = new Image(25, 25);
        toc3on.src = "images/butt_mute2_h.gif";
        toc4on = new Image(25, 25);
        toc4on.src = "images/butt_attiva_h.gif";
        toc5on = new Image(25, 25);
        toc5on.src = "images/butt_speaker_h.gif";
		
        toc1off = new Image(25, 25);
        toc1off.src = "images/butt_mute.gif";
        toc2off = new Image(25, 25);
        toc2off.src = "images/butt_riattacca.gif";
	toc3off = new Image(25, 25);
        toc3off.src = "images/butt_mute2.gif";
        toc4off = new Image(25, 25);
        toc4off.src = "images/butt_attiva.gif";
        toc5off = new Image(25, 25);
        toc5off.src = "images/butt_earphone.gif";
				
        }

function img_act(imgName) {
        if (browser) {
        imgOn = eval(imgName + "on.src");
        document [imgName].src = imgOn;
        }
}

function img_inact(imgName) {
        if (browser) {
        imgOff = eval(imgName + "off.src");
        document [imgName].src = imgOff;
        }
}