dom = (document.getElementById)? true : false;
nn4 = (document.layers)? true : false;
ie4 = (!dom && document.all)? true : false;

var start = 0;  
var activmenu = 0;  
var cur = 0;  
var tim;
var overactiv = 0;  

function showmenu(el) 
{ 
 if (dom) document.getElementById(el).style.visibility = "visible";
 else if (ie4) document.all[el].style.visibility = "visible";
 else if (nn4) document.layers[el].visibility = "show";
 activmenu = 1;
}

function hidemenu(el) 
{
 if (el!="") {
 if (dom) document.getElementById(el).style.visibility = "hidden";
 else if (ie4) document.all[el].style.visibility = "hidden";
 else if (nn4) document.layers[el].visibility = "hide";
 activmenu = 0;
}
}




function activ(el) 
{
if (activmenu == 1) 
{
if (el != cur) {hidemenu(cur); showmenu(el); cur = el;}
} 
   else {showmenu(el); cur = el; }
}
function timeactiv()
{
 overactiv=0;
 tim=setTimeout('tactiv()','700'); 
}
function tactiv()
{
if (overactiv == 0 && activmenu == 1) hidemenu(cur); 
}

function timedisable()
{
if (start != 0) 
{clearTimeout(tim);  overactiv=1}
else start = 1;
}