function showMenu(id, above) {
  var btn = document.getElementById("btn"+id);
  var menu = document.getElementById("menu"+id);

  if (above > 0) {
    menu.style.top = ((parseInt(btn.style.top.substr(0, btn.style.top.length-2)) + 140) - above) + "px";
  } else {
    menu.style.top = (parseInt(btn.style.top.substr(0, btn.style.top.length-2)) + 140) + "px";
  }
  menu.style.left = "125px";
  menu.style.visibility = "visible";

}

function showTopMenu(id) {
  var btn = document.getElementById("btn_top"+id);
  var menu = document.getElementById("menu_top"+id);
  menu.style.left = (parseInt(btn.style.left.substr(0, btn.style.left.length-2)) + 5) + "px";
  menu.style.top = "118px";
  menu.style.visibility = "visible";

}

function hideTopMenu(id) {
  var menu = document.getElementById("menu_top"+id);
  menu.style.visibility = "hidden";
}

function hideMenu(id) {
  var menu = document.getElementById("menu"+id);
  menu.style.visibility = "hidden";
}

function switchImg(img_id, mouse_over) {
  var img = document.getElementById(img_id);
  if (mouse_over) {
    img.style.backgroundImage = "url(images/arrow_orange_small.jpg)";
  } else {
    img.style.backgroundImage = "url(images/arrow_black_small.jpg)";
  }
}