var timeout = 500;
var closetimer = 0;
var menuitem = 0;
var btn_h = "";

function button_close()
{
  switch (btn_h) {
  case "submenu1":
    document.btn1.src='images/screen/btn-startseite_126x42.gif';
    btn_h = "";
    break;
  case "submenu2":
    document.btn2.src='images/screen/btn_unternehmensdaten_199x42.gif';
    btn_h = "";
    break;
  case "submenu3":
    document.btn3.src='images/screen/btn_service_103x42.gif';
    btn_h = "";
    break;
  case "submenu4":
    document.btn4.src='images/screen/btn_kontakt_109x42.gif';
    btn_h = "";
    break;
  default:
    break;
  };
}

function menu_open(id)
{	
	menu_cancelclosetime();
  
	if (menuitem)
  {
    menuitem.style.visibility = 'hidden';
    button_close();
  };
   
  switch (id) {
  case "submenu1":
    document.btn1.src='images/screen/btn-startseite-h_126x42.gif';
    btn_h = "submenu1";
    break;
  case "submenu2":
    document.btn2.src='images/screen/btn_unternehmensdaten-h_199x42.gif';
    btn_h = "submenu2";
    break;
  case "submenu3":
    document.btn3.src='images/screen/btn_service-h_103x42.gif';
    btn_h = "submenu3";
    break;
  case "submenu4":
    document.btn4.src='images/screen/btn_kontakt-h_109x42.gif';
    btn_h = "submenu4";
    break;
  default:
    break;
  };
  
	menuitem = document.getElementById(id);
  setTimeout('menuitem.style.visibility = \'visible\'', 140);
	
}

function menu_close()
{
	if (menuitem) menuitem.style.visibility = 'hidden';
  button_close();
}

function menu_closetime()
{
	closetimer = window.setTimeout(menu_close, timeout);
}

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

function popup(url)
{
fenster = window.open(url, "HDIOnlineBerechnung", "width=780,height=630,resizable=yes,scrollbars=yes,toolbar=no,menubar=no");
fenster.focus();
return false;
}

document.onclick = menu_close;