var menuItemHeight = 33;
var menuDropdownWidth = 150;

function findPosX(obj) {
  var curleft = 0;
  if(obj.offsetParent)
      while(1) {
        curleft += obj.offsetLeft;
        if(!obj.offsetParent) break;
        obj = obj.offsetParent;
      }
  else if(obj.x) curleft += obj.x;
  return curleft;
}

function findPosY(obj) {
  var curtop = 0;
  if(obj.offsetParent)
    while(1) {
        curtop += obj.offsetTop;
        if(!obj.offsetParent) break;
        obj = obj.offsetParent;
      }
  else if(obj.y) curtop += obj.y;
  return curtop;
}

function setBG(div, url) { div.style.backgroundImage = "url('" + url + "')"; }

var timers = new Array(5);

function menuHover(div, num, offset) {
  if (!offset) offset = 0;
  if (timers[num]) clearTimeout(timers[num]);
  setBG(div, "images/nav/nav_bgsm_over_0" + num + ".png");
  setTimeout(function() { showMenu(div, num, offset) }, 0);
}

function showMenu(div, num, offset) {
  var innerDivs = div.getElementsByTagName("div");
  if(innerDivs.length == 0) { return; }
  var menu = innerDivs[0];
  menu.style.left = (findPosX(div) + offset - 1) + "px";
  menu.style.top = (findPosY(div) + menuItemHeight)  + "px";
  menu.style.width = menuDropdownWidth + "px";
  menu.style.display = "block";
}

function menuUnHover(div, num) {
  setBG(div, "images/nav/nav_bgsm_0" + num + ".png");
  timers[num] = setTimeout(function () { hideMenu(div, num) }, 0);
}

function hideMenu(div, num) {
  var innerDivs = div.getElementsByTagName("div");
  if(innerDivs.length == 0) { return; }
  var menu = innerDivs[0];
  menu.style.display = "none"; 
}

function tabHover(div)   { setBG(div, "images/content_tab/tab_arrow_over.png"); }
function tabUnHover(div) { setBG(div, "images/content_tab/tab_arrow.png"); }