var agt=navigator.userAgent.toLowerCase();

    var is_major = parseInt(navigator.appVersion);
    var is_minor = parseFloat(navigator.appVersion);

    var is_nav  = ((agt.indexOf('mozilla')!=-1) && (agt.indexOf('spoofer')==-1)
                && (agt.indexOf('compatible') == -1) && (agt.indexOf('opera')==-1)
                && (agt.indexOf('webtv')==-1) && (agt.indexOf('hotjava')==-1)
				 && (agt.indexOf('gecko') == -1));
    var is_nav4up = (is_nav && (is_minor >= 4.0));

    var is_ie     = ((agt.indexOf("msie") != -1) && (agt.indexOf("opera") == -1));
    var is_ie4up  = (is_ie && (is_major >= 4));
	
	var is_opera = (agt.indexOf("opera") != -1);
    var is_opera2 = (agt.indexOf("opera 2") != -1 || agt.indexOf("opera/2") != -1);
    var is_opera3 = (agt.indexOf("opera 3") != -1 || agt.indexOf("opera/3") != -1);
    var is_opera4 = (agt.indexOf("opera 4") != -1 || agt.indexOf("opera/4") != -1);
    var is_opera5 = (agt.indexOf("opera 5") != -1 || agt.indexOf("opera/5") != -1);
    var is_opera5up = (is_opera && !is_opera2 && !is_opera3 && !is_opera4);

	var use_menu = true;
	
	if((is_nav && !is_nav4up) || (is_ie && !is_ie4up) || (is_opera && !is_opera5up))
		use_menu = false;
	
	var is_mac    = (agt.indexOf("mac")!=-1);