function setDefaultMenu() {
  var submenus = document.getElementsByClassName('submenu');

  for(i = 0; i < submenus.length; i++) {
    submenus[i].style.display = 'none';
  }

  var activeLinks = document.getElementsByClassName('active');

  if(activeLinks.length > 0) {
    var children = activeLinks[0].childNodes;

    for(i = 0; i < children.length; i++) {
      if(children[i].nodeName == "UL") {
        children[i].style.display = "block";
        return;
      }
    }
  }
}

function showThisHideOthers(id) {
  var submenus = document.getElementsByClassName('submenu');

  for(i = 0; i < submenus.length; i++) {
    submenus[i].style.display = 'none';
  }

  for(i = 0; i < $(id).parentNode.childNodes.length; i++) {
    if($(id).parentNode.childNodes[i].nodeName == "UL") {
      $(id).parentNode.childNodes[i].style.display = "block";
      return;
    }
  }
}

function setActive(id) {
  var activeLinks = document.getElementsByClassName('active');

  for(i = 0; i < activeLinks.length; i++) {
    activeLinks[i].className = '';
  }

  $(id).parentNode.className = 'active';
}

function init() {
  setDefaultMenu();

  $('nav_document').parentNode.onmouseover = function() {showThisHideOthers('nav_document');};
  $('nav_logistics').parentNode.onmouseover = function() {showThisHideOthers('nav_logistics');};
  $('nav_staffing').parentNode.onmouseover = function() {showThisHideOthers('nav_staffing');};

  $('nav_document').parentNode.onmouseout = function() {setDefaultMenu();};
  $('nav_logistics').parentNode.onmouseout = function() {setDefaultMenu();};
  $('nav_staffing').parentNode.onmouseout = function() {setDefaultMenu();};

  // $('nav_document').onclick = function() { setActive('nav_document'); return false; };
  // $('nav_logistics').onclick = function() { setActive('nav_logistics'); return false; };
  // $('nav_staffing').onclick = function() { setActive('nav_staffing'); return false; };
}

window.onload = init;