var ns4up = (document.layers) ? 1 : 0;  // browser sniffer
var ie4up = (document.all) ? 1 : 0;
var ns6up = (document.getElementById&&!document.all) ? 1 : 0;

var agt=navigator.userAgent.toLowerCase();
var is_nav  = ((agt.indexOf('mozilla')!=-1) && (agt.indexOf('netscape')==-1));    

/*var agt=navigator.userAgent.toLowerCase();
var is_nav  = ((agt.indexOf('mozilla')!=-1) && (agt.indexOf('netscape')==-1));    

if(is_nav){
	if(ie4up){
		alert('ie')
	}
	else
	{
		alert('mozilla')
	}
}
else{
	alert('netscape')
}*/

function show(sub)
{
	for (i=1;i<=nav_id;i++) {
		hide("subnav_" + i);
	}

	if (ie4up || ns6up) {
		if (ie4up) {
			if (document.all[sub] && document.all[sub].style) {
                if (document.all[sub].style.display == "inline") {
                    document.all[sub].style.display = "none";
                } else {
                    document.all[sub].style.display = "inline";
                }
            }
		} else {
			if (document.getElementById(sub)) {
                if (document.getElementById(sub).style.visibility == "visible") {
                    document.getElementById(sub).style.visibility = "hidden";
                    document.getElementById(sub).style.display = "none";
                } else {
                    document.getElementById(sub).style.visibility = "visible";
                    document.getElementById(sub).style.display = "inline";
                }
            }
		}
	} else if (ns4up){
		if (document.layers[sub]) {
            if (document.layers[sub].visibility == "visible") {
                document.layers[sub].visibility = "hidden";
            } else {
                document.layers[sub].visibility = "visible";
            }
        }
	}
}

function hide(sub)
{
	if (ie4up || ns6up) {
		if (ie4up) {
			if (document.all[sub] && document.all[sub].style) {
				document.all[sub].style.display = "none";
			}
		} else {
			if (document.getElementById(sub)) {
				document.getElementById(sub).style.visibility = "hidden";
			}
		}
	} else if (ns4up) {
		if (document.layers[sub]) {
			document.layers[sub].visibility = "hidden";
		}
	}
}