var timeout         = 500;
var closetimer      = 0;
var ddmenuitem      = 0;

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