var timeout         = 1;
var closetimer		= 0;
var ddmenuitem      = 0;
        
// open hidden layer
function mopen(id)
{	
    // cancel close timer
    mcancelclosetime();
        
    // close old layer
    if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';
        
    // get new layer and show it
    ddmenuitem = document.getElementById(id);
    ddmenuitem.style.visibility = 'visible';
        
}
// close showed layer
function mclose()
{
    if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';
}
        
// go close timer
function mclosetime()
{
    closetimer = window.setTimeout(mclose, timeout);
}
        
// cancel close timer
function mcancelclosetime()
{
    if(closetimer)
    {
        window.clearTimeout(closetimer);
        closetimer = null;
    }
}
        
// close layer when click-out
document.onclick = mclose;