var menucount = 5;

var dom = document.getElementById ? true : false;
var ie4 = ((document.all) && (!dom)) ? true : false;
var ns4 = document.layers ? true : false;
var opera = navigator.userAgent.indexOf('Opera') != -1 ? true : false;
var dhtml = dom ? true : ie4 ? true : ns4 ? true : false;

function setVisibility(element,newVisibility) {
	if (dhtml) {
		if (dom) document.getElementById(element).style.display = newVisibility;
		else if (ie4) document.all[element].style.display = newVisibility;
		else if (ns4) eval('document.' + element + '.display = newVisibility');
	} 
}

function showMenu(id) {
	if (dhtml) {
	    document.cookie = 'menu='+id;
		for (var i = 0; i <= menucount; i++)
			if (i != id) setVisibility('menu_'+i,'none');
		setVisibility('menu_'+id,'');
	}
}

function showMenuOnStart() {
    if (document.cookie != null) {
        var aCookie = document.cookie.split(';');
        for (var i=0; i < aCookie.length; i++) {
            var aCookieItem = aCookie[i].split('=');
            if ('menu' == aCookieItem[0]) {
                showMenu(aCookieItem[1]);
                return;
            }
        }
    }
    showMenu('0');
}