function getBG()
{
  var tb = window.document;
  if (tb.documentElement && tb.documentElement.style && tb.documentElement.style.backgroundColor) {
    return tb.documentElement.style.backgroundColor;
  }
  if (tb.body && tb.body.style && tb.body.style.backgroundColor) {
    return tb.body.style.backgroundColor;
  }
  if (tb.documentElement && tb.documentElement.style && tb.documentElement.style.background) {
    return tb.documentElement.style.background;
  }
  if (tb.body && tb.body.style && tb.body.style.background) {
    return tb.body.style.background;
  }
  if (tb.bgColor) {
    return tb.bgColor;
  }
  return '#ffffff';
}

function split(colour, which_pair) {
  return HexToDec(colour.substring(1+ (which_pair* 2),
                                   3+ (which_pair* 2)));
}

function getHex(r,g,b) {
  return '#'+DecToHex(r)+DecToHex(g)+DecToHex(b);
}

var hexbase="0123456789ABCDEF";
function DecToHex(number) {
  return hexbase.charAt((number>> 4)& 0xf)+ hexbase.charAt(number& 0xf);
}

function HexToDec(number) {
  return parseInt(number.toUpperCase(), 16);
}

function shade(color)
{
  var mod = .79;
  r = split(color,0) * mod;
  g = split(color,1) * mod;
  b = split(color,2) * mod;
  new_color = '#'+DecToHex(r)+DecToHex(g)+DecToHex(b);
  return(new_color);
}

function drop_shadow(obj,hor,ver,left,top,width,height,color)
{
  if (color=="#000000") {
    return;
  }
  shaded = shade(color);
  i = document.createElement("DIV");
  i.style.position="absolute";
  i.style.left=left+hor;
  i.style.top=top+ver;
  i.style.width=width;
  i.style.height=(height-hor);
  i.style.zIndex=-1;
  i.style.backgroundColor=shaded;
  i.style.visibility = "visible";
  i.innerHtml=' ';
  i.height=i.style.height;
  obj.appendChild(i);
}

function init_shelf()
{
  var bgcolor = getBG();
  var shelf = document.getElementById("main_menu");
  if (shelf) {
    // shelf shading
    // drop_shadow(shelf,0,6,browserObjectX(shelf),browserObjectY(shelf)+shelf.offsetHeight,"100%",16,bgcolor);
    // drop_shadow(shelf,0,4,browserObjectX(shelf),browserObjectY(shelf)+shelf.offsetHeight,"100%",16,shade(bgcolor));
    // drop_shadow(shelf,0,2,browserObjectX(shelf),browserObjectY(shelf)+shelf.offsetHeight,"100%",16,shade(shade(bgcolor)));

    // draw folder arrows
    var books = shelf.getElementsByTagName("a");
    for (book = 0; book < books.length; book++) {
      b = books[book];
      if (b.onclick) {
        i = document.createElement("IMG");
        i.src = "/shelf_open.gif";
        i.width=16;
        i.height=16;
        i.border = 0;
        i.style.position= "absolute";
        i.style.left=b.offsetWidth/2 - 8;
        if (browser.isIE) {
          i.style.top=shelf.offsetHeight;
        } else {
          i.style.top=browserObjectY(shelf)+16;
        }
        i.style.zIndex=9999;
        i.style.visibility = "visible";
        b.appendChild(i);
      }
      // book shading
      im=b.getElementsByTagName("IMG").item(0);
      x=browserObjectX(b);
      y=browserObjectY(b);
      // drop_shadow(shelf,12,4,x,y,im.width+4,im.height+8,bgcolor);
      // drop_shadow(shelf,12,6,x,y,im.width+2,im.height+8,shade(bgcolor));
      // drop_shadow(shelf,12,8,x,y,im.width,im.height+8,shade(shade(bgcolor)));
    }
  }
}

// this code is ours

var select_list = new Array();
var select_count=0;

function init_select()
{
  if (document.all && !select_count) {
    window.status='Initializing Menu, Please Wait...';
    for (f=0; f<document.forms.length; f++) {
      for (ff=0; ff<document.forms[f].length; ff++) {
        if (document.forms[f].elements[ff].type=='select-one' || document.forms[f].elements[ff].type=='select-multiple') {
          select_list[select_count++] = document.forms[f].elements[ff];
        }
      }
    }
    window.status='';
  }
}

function disable_select()
{
  if (!selects_disabled) {
    init_select();
    for (i=0; i<select_count; i++) {
      select_list[i].style.visibility='hidden';
    }
    selects_disabled = true;
  }
}


function enable_select()
{
  if (selects_disabled) {
    init_select();
    for (i=0; i<select_count; i++) {
      select_list[i].style.visibility='visible';
    }
    selects_disabled = false;
  }
}

// the actual menu code is from brainjar.com

//*****************************************************************************
// Do not remove this notice.
//
// Copyright 2000-2004 by Mike Hall.
// See http://www.brainjar.com for terms of use.
//*****************************************************************************

// browser code moved to browser.js

//----------------------------------------------------------------------------
// Code for handling the menu bar and active button.
//----------------------------------------------------------------------------

var activeButton = null;

/* [MODIFIED] This code commented out, not needed for activate/deactivate
   on mouseover.

// Capture mouse clicks on the page so any active button can be
// deactivated.

if (browser.isIE)
  document.onmousedown = pageMousedown;
else
  document.addEventListener("mousedown", pageMousedown, true);

function pageMousedown(event) {

  var el;

  // If there is no active button, exit.

  if (activeButton == null)
    return;

  // Find the element that was clicked on.

  if (browser.isIE)
    el = window.event.srcElement;
  else
    el = (event.target.tagName ? event.target : event.target.parentNode);

  // If the active button was clicked on, exit.

  if (el == activeButton)
    return;

  // If the element is not part of a menu, reset and clear the active
  // button.

  if (getContainerWith(el, "DIV", "menu") == null) {
    resetButton(activeButton);
    activeButton = null;
  }
}

[END MODIFIED] */

function buttonClick(event, menuId) {

  var button;

  // Get the target button element.

  if (browser.isIE)
    button = window.event.srcElement;
  else
    button = event.currentTarget;

  // Blur focus from the link to remove that annoying outline.

  button.blur();

  // Associate the named menu to this button if not already done.
  // Additionally, initialize menu display.

  if (button.menu == null) {
    button.menu = document.getElementById(menuId);
    if (button.menu.isInitialized == null)
      menuInit(button.menu);
  }

  // [MODIFIED] Added for activate/deactivate on mouseover.

  // Set mouseout event handler for the button, if not already done.

  if (button.onmouseout == null)
    button.onmouseout = buttonOrMenuMouseout;

  // Exit if this button is the currently active one.

  if (button == activeButton)
    return false;

  // [END MODIFIED]

  // Reset the currently active button, if any.

  if (activeButton != null)
    resetButton(activeButton);

  // Activate this button, unless it was the currently active one.

  if (button != activeButton) {
    depressButton(button);
    activeButton = button;
  }
  else
    activeButton = null;

  disable_select(); // bmn

  return false;
}

function buttonMouseover(event, menuId) {

  var button;

  // [MODIFIED] Added for activate/deactivate on mouseover.

  // Activates this button's menu if no other is currently active.

  if (activeButton == null) {
    buttonClick(event, menuId);
    return;
  }

  // [END MODIFIED]

  // Find the target button element.

  if (browser.isIE)
    button = window.event.srcElement;
  else
    button = event.currentTarget;

  // If any other button menu is active, make this one active instead.

  if (activeButton != null && activeButton != button)
    buttonClick(event, menuId);
}

function depressButton(button) {

  var x, y;

  // Update the button's style class to make it look like it's
  // depressed.

  button.className += " menuButtonActive";

  // [MODIFIED] Added for activate/deactivate on mouseover.

  // Set mouseout event handler for the button, if not already done.

  if (button.onmouseout == null)
    button.onmouseout = buttonOrMenuMouseout;
  if (button.menu.onmouseout == null)
    button.menu.onmouseout = buttonOrMenuMouseout;

  // [END MODIFIED]

  // Position the associated drop down menu under the button and
  // show it.

  bar=getContainerWith(button,"DIV","menuBar");
  x = browserObjectX(button);
  y = browserObjectY(bar) + bar.offsetHeight;

  button.menu.style.left = x + "px";
  button.menu.style.top  = y + "px";
  button.menu.style.visibility = "visible";
}

function resetButton(button) {

  // Restore the button's style class.

  removeClassName(button, "menuButtonActive");

  enable_select(); // bmn

  // Hide the button's menu, first closing any sub menus.

  if (button.menu != null) {
    closeSubMenu(button.menu);
    button.menu.style.visibility = "hidden";
  }
}

//----------------------------------------------------------------------------
// Code to handle the menus and sub menus.
//----------------------------------------------------------------------------

function menuMouseover(event) {

  var menu;

  // Find the target menu element.

  if (browser.isIE)
    menu = getContainerWith(window.event.srcElement, "DIV", "menu");
  else
    menu = event.currentTarget;

  // Close any active sub menu.

  if (menu.activeItem != null)
    closeSubMenu(menu);
}

function menuItemMouseover(event, menuId) {

  var item, menu, x, y;

  // Find the target item element and its parent menu element.

  if (browser.isIE)
    item = getContainerWith(window.event.srcElement, "A", "menuItem");
  else
    item = event.currentTarget;
  menu = getContainerWith(item, "DIV", "menu");

  // Close any active sub menu and mark this one as active.

  if (menu.activeItem != null)
    closeSubMenu(menu);
  menu.activeItem = item;

  disable_select(); // bmn

  // Highlight the item element.

  item.className += " menuItemHighlight";

  // Initialize the sub menu, if not already done.

  if (item.subMenu == null) {
    item.subMenu = document.getElementById(menuId);
    if (item.subMenu.isInitialized == null)
      menuInit(item.subMenu);
  }

  // [MODIFIED] Added for activate/deactivate on mouseover.

  // Set mouseout event handler for the sub menu, if not already done.

  if (item.subMenu.onmouseout == null)
    item.subMenu.onmouseout = buttonOrMenuMouseout;

  // [END MODIFIED]

  // Get position for submenu based on the menu item.

  x = browserObjectX(item) + item.offsetWidth;
  y = browserObjectY(item);

  // Adjust position to fit in view.

  var maxX, maxY;

  if (browser.isIE) {
    maxX = Math.max(document.documentElement.scrollLeft, document.body.scrollLeft) +
      (document.documentElement.clientWidth != 0 ? document.documentElement.clientWidth : document.body.clientWidth);
    maxY = Math.max(document.documentElement.scrollTop, document.body.scrollTop) +
      (document.documentElement.clientHeight != 0 ? document.documentElement.clientHeight : document.body.clientHeight);
  }
  if (browser.isOP) {
    maxX = document.documentElement.scrollLeft + window.innerWidth;
    maxY = document.documentElement.scrollTop  + window.innerHeight;
  }
  if (browser.isNS) {
    maxX = window.scrollX + window.innerWidth;
    maxY = window.scrollY + window.innerHeight;
  }
  maxX -= item.subMenu.offsetWidth;
  maxY -= item.subMenu.offsetHeight;

  if (x > maxX)
    x = Math.max(0, x - item.offsetWidth - item.subMenu.offsetWidth
      + (menu.offsetWidth - item.offsetWidth));
  y = Math.max(0, Math.min(y, maxY));

  // Position and show the sub menu.

  item.subMenu.style.left = x + "px";
  item.subMenu.style.top  = y + "px";
  item.subMenu.style.visibility = "visible";

  // Stop the event from bubbling.

  if (browser.isIE)
    window.event.cancelBubble = true;
  else
    event.stopPropagation();
}

function closeSubMenu(menu) {

  if (menu == null || menu.activeItem == null)
    return;

  // Recursively close any sub menus.

  if (menu.activeItem.subMenu != null) {
    closeSubMenu(menu.activeItem.subMenu);
    menu.activeItem.subMenu.style.visibility = "hidden";
    menu.activeItem.subMenu = null;
  }
  removeClassName(menu.activeItem, "menuItemHighlight");
  menu.activeItem = null;
}

// [MODIFIED] Added for activate/deactivate on mouseover. Handler for mouseout
// event on buttons and menus.

function buttonOrMenuMouseout(event) {

  var el;

  // If there is no active button, exit.

  if (activeButton == null)
    return;

  // Find the element the mouse is moving to.

  if (browser.isIE)
    el = window.event.toElement;
  else if (event.relatedTarget != null)
    el = (event.relatedTarget.tagName ? event.relatedTarget : event.relatedTarget.parentNode);

  if (!el) {
    return;
  }

  // If the element is not part of a menu, reset the active button.

  if (getContainerWith(el, "DIV", "menu") == null) {
    resetButton(activeButton);
    activeButton = null;
  }
}

// [END MODIFIED]

//----------------------------------------------------------------------------
// Code to initialize menus.
//----------------------------------------------------------------------------

function menuInit(menu) {

  var itemList, spanList;
  var textEl, arrowEl;
  var itemWidth;
  var w, dw;
  var i, j;

  // For IE, replace arrow characters.

  if (browser.isIE) {
    menu.style.lineHeight = "2.5ex";
    spanList = menu.getElementsByTagName("SPAN");
    for (i = 0; i < spanList.length; i++)
      if (hasClassName(spanList[i], "menuItemArrow")) {
        spanList[i].style.fontFamily = "Webdings";
        spanList[i].firstChild.nodeValue = "4";
      }
  }

  // Find the width of a menu item.

  itemList = menu.getElementsByTagName("A");
  if (itemList.length > 0)
    itemWidth = itemList[0].offsetWidth;
  else
    return;

  // For items with arrows, add padding to item text to make the
  // arrows flush right.

  for (i = 0; i < itemList.length; i++) {
    spanList = itemList[i].getElementsByTagName("SPAN");
    textEl  = null;
    arrowEl = null;
    for (j = 0; j < spanList.length; j++) {
      if (hasClassName(spanList[j], "menuItemText"))
        textEl = spanList[j];
      if (hasClassName(spanList[j], "menuItemArrow"))
        arrowEl = spanList[j];
    }
    if (textEl != null && arrowEl != null) {
      textEl.style.paddingRight = (itemWidth 
        - (textEl.offsetWidth + arrowEl.offsetWidth)) + "px";
      // For Opera, remove the negative right margin to fix a display bug.
      if (browser.isOP)
        arrowEl.style.marginRight = "0px";
    }
  }

  // Fix IE hover problem by setting an explicit width on first item of
  // the menu.

  if (browser.isIE) {
    w = itemList[0].offsetWidth;
    itemList[0].style.width = w + "px";
    dw = itemList[0].offsetWidth - w;
    w -= dw;
    itemList[0].style.width = w + "px";
  }

  // Mark menu as initialized.

  menu.isInitialized = true;
}

//----------------------------------------------------------------------------
// General utility functions.
//----------------------------------------------------------------------------

function getContainerWith(node, tagName, className) {

  // Starting with the given node, find the nearest containing element
  // with the specified tag name and style class.

  while (node != null) {
    if (node.tagName != null && node.tagName == tagName &&
        hasClassName(node, className))
      return node;
    node = node.parentNode;
  }

  return node;
}

function hasClassName(el, name) {

  var i, list;

  // Return true if the given element currently has the given class
  // name.

  if (el.className) {
    list = el.className.split(" ");
    for (i = 0; i < list.length; i++)
      if (list[i] == name)
        return true;
  }

  return false;
}

function removeClassName(el, name) {

  var i, curList, newList;

  if (el.className == null)
    return;

  // Remove the given class name from the element's className property.

  newList = new Array();
  curList = el.className.split(" ");
  for (i = 0; i < curList.length; i++)
    if (curList[i] != name)
      newList.push(curList[i]);
  el.className = newList.join(" ");
}