var timeout= 500;
var closetimer= 0;
var dropmenuitem= 0;

function dropopen(id)
{
dropcancelclosetime();

if(dropmenuitem) dropmenuitem.style.visibility = 'hidden';

dropmenuitem = document.getElementById(id);
dropmenuitem.style.visibility = 'visible';

}
function dropclose()
{
if(dropmenuitem) dropmenuitem.style.visibility = 'hidden';
}

function dropclosetime()
{
closetimer = window.setTimeout(dropclose, timeout);
}

function dropcancelclosetime()
{
if(closetimer)
{
window.clearTimeout(closetimer);
closetimer = null;
}
}

document.onclick = dropclose;