function startScrollingDetector() {
  setInterval("scrollingDetector()", 250);
}


function scrollingDetector() {
  min_x = 128;
  offset = 11;
  if (navigator.appName == "Microsoft Internet Explorer")
  {      
    if (!document.documentElement.scrollTop)
      if (document.body.scrollTop > min_x) {
        document.getElementById("menu").style.top = document.body.scrollTop - offset; 
      } else {
        document.getElementById("menu").style.top = min_x; 
      }
    else 
      if (document.documentElement.scrollTop > min_x) {
        document.getElementById("menu").style.top = document.documentElement.scrollTop - offset; 
      } else {
        document.getElementById("menu").style.top = min_x;
      }
  }
  else {
    if (window.pageYOffset > min_x) {
      document.getElementById("menu").style.top = (window.pageYOffset - offset) + "px"; 
    }
    else {
      document.getElementById("menu").style.top = min_x + "px"; 
    }
  }
}

function doHideMenus() {
  document.getElementById('menu_dd1').style.display="none";
  document.getElementById('menu_dd2').style.display="none";
  document.getElementById('menu_dd3').style.display="none";
  document.getElementById('menu_dd4').style.display="none";
}

function hideDIV(me) {
  document.getElementById(me).style.display="none";
}

function showDIV(me) {
  doHideMenus();
  document.getElementById(me).style.display="block";
}