/* menuDropdown.js - implements a dropdown menu based on a HTML list
 * Author: Dave Lindquist (http://www.gazingus.org)
 * Modified by: Nicolas Lesbats (nicolas lesbats at laposte net)
 * Version: 0.1b (2004-03-11)
 */

var maxWidth = 20;
/* maximum width of the submenus (in 'em' units) */

var borderBox = false;
var horizontal = new Array();
var menuTop  = new Array();
var menuHeight = new Array();
var menuLeft  = new Array();
var menuWidth = new Array();

window.onload = function() { loadMenu(); }

function loadMenu() {
 if (!document.getElementById) return;
 var i = 0, j, root, submenus, node, li, link, division;
 while (true) {
  root = document.getElementById("menuList" + (i + 1));
  if (root == null)
   break;
  submenus = root.getElementsByTagName("ul");
  division = root.parentNode;

  if (document.createElement) {
   /* Win/IE5-6 trick: makes the whole width of the submenus clickable
    */
   for (j = 0; j< submenus.length; j++) {
    node = submenus.item(j);
    if (node.className == "menu" && node.getElementsByTagName("ul").length == 0) {
     li = document.createElement("li");
     node.appendChild(li);
     li.style.position = "absolute";
     li.style.visibility = "hidden";
    }
   }
   /* checks whether the 'width' property applies to the border box or
    * the content box of an element
    */
   if (i == 0) {
    li.style.display = "block";
    li.style.padding = "0";
    li.style.width  = "2px";
    li.style.border = "1px solid";
    if (li.offsetWidth == 2)
     borderBox = true;
   }
  }

  initializeMenu(root, division, i);

  for (j = 0; j< submenus.length; j++) {
   node = submenus.item(j);
   if (node.className == "menu") {
    link = node.previousSibling;
    while (link != null) {
     if (link.className == "actuator") {
      initializeSubmenu(node, link, root, division);
      node.set();
      break;
     }
     link = link.previousSibling;
    }
   }
  }
  i++;
 }
}

function initializeMenu(root, div, index) {

 horizontal[index] = menuIsHorizontal(root);
 menuTop[index]  = div.offsetTop;
 menuHeight[index] = div.offsetHeight;
 menuLeft[index]  = div.offsetLeft;
 menuWidth[index] = div.offsetWidth;

 div.horizontal = function() {
  return horizontal[index];
 }

 div.checkMove = function() {
  if (this.hasMoved()) this.resetMenu();
 }

 div.hasMoved = function() {
  if (menuTop[index]  == this.offsetTop  &&
    menuHeight[index] == this.offsetHeight &&
    menuLeft[index]  == this.offsetLeft  &&
    menuWidth[index] == this.offsetWidth)
   return false;
  return true;
 }

 div.resetMenu = function() {
  horizontal[index] = menuIsHorizontal(root);
  menuTop[index]  = this.offsetTop;
  menuHeight[index] = this.offsetHeight;
  menuLeft[index]  = this.offsetLeft;
  menuWidth[index] = this.offsetWidth;

  var submenus = root.getElementsByTagName("ul");
  for (var j = 0; j< submenus.length; j++) {
   var node = submenus.item(j);
   if (node.className == "menu") {
    node.style.right = "";
    node.style.left = "";
    if (!window.opera)
     node.style.width = "";
    node.set();
   }
  }
 }
}

function menuIsHorizontal(root) {
 var first = firstElement(root, "LI");
 if (first != null) {
  var second = first.nextSibling;
  while (second != null) {
   if (second.tagName == "LI") {
    first = firstElement(first, "A");
    second = firstElement(second, "A");
    if (first != null && second != null)
     if (first.offsetLeft == second.offsetLeft)
      return false;
    return true;
   }
   second = second.nextSibling;
  }
 }
 return true;
}

function initializeSubmenu(menu, actuator, root, div) {

 var parent = menu.parentNode;

 parent.onmouseover = function() {
  div.checkMove();
  menu.style.visibility = "visible";
 }

 actuator.onfocus = function() {
  div.checkMove();
  menu.style.visibility = "visible";
 }

 parent.onmouseout = function() {
  menu.style.visibility = "";
 }

 var tags = menu.getElementsByTagName("a");
 var link = tags.item(tags.length - 1);
 if (!link.onblur)
  link.onblur = function() {
   var node = link.parentNode.parentNode;
   while (node != menu) {
    node.style.visibility = "";
    node = node.parentNode.parentNode;
   }
   menu.style.visibility = "";
  }

 if (parent.parentNode == root) {
  menu.set = function() {
   setLocation1(this, actuator, root, div);
  }
 } else {
  menu.set = function() {
   setLocation2(this, actuator, div);
  }
 }
}

function setLocation1(menu, actuator, root, div) {
 var first = firstElement(menu, "LI");
 if (first != null)
  if (first.offsetParent == menu)
   setWidth(menu);
 if (div.horizontal()) {
  if (actuator.offsetParent == menu.offsetParent) {
   menu.style.left = actuator.offsetLeft + "px";
   menu.style.top = actuator.offsetTop + actuator.offsetHeight + "px";
  } else {
   /* happens in Win/IE5-6 when some ancestors are 'static' and have their
    * 'width' or 'height' different than 'auto' */
   var parent = actuator.offsetParent;
   var top = 0;
   var left = 0;
   while (parent != menu.offsetParent && parent != null) {
    top = top + parent.offsetTop;
    left = left + parent.offsetLeft;
    parent = parent.offsetParent;
   }
   menu.style.left = left + actuator.offsetLeft + "px";
   menu.style.top = top + actuator.offsetTop + actuator.offsetHeight + "px";
  }
 } else {
  menu.style.top = actuator.offsetTop + "px";
  menu.style.left = (div.offsetWidth + actuator.offsetWidth) / 2 + "px";
 }
}

function setLocation2(menu, actuator, div) {
 if (menu.offsetParent != document.body)
  setWidth(menu);
 menu.style.top = actuator.offsetTop + "px";
 menu.style.left = actuator.offsetWidth + "px";
}

function setWidth(menu) {
 menu.style.right = - maxWidth + "em";
 var width = 0;
 var height = 0;
 var items = menu.getElementsByTagName("a");
 for (var i = 0; i< items.length; i++) {
  var link = items.item(i);
  if (link.parentNode.parentNode == menu) {
   height = height + link.offsetHeight;
   if (link.offsetWidth >width)
    width = link.offsetWidth;
  }
 }
 if (borderBox)
  width = width + (menu.offsetHeight - height);
 menu.style.width = width + "px";
}

function firstElement(node, name) {
 var first = node.firstChild;
 while (first != null) {
  if (first.tagName == name)
   return first;
  first = first.nextSibling;
 }
 return null;
}