/******************************************************************************
* Copyright 2000 by Mike Hall                                                 *
* Please see http://www.brainjar.com for terms of use.                        *
*                                                                             *
* Code for the site menu.                                                     *
*                                                                             *
* Updated 10/30/2001 to add Opera support.                                    *
******************************************************************************/

// Determine browser and version. Script works for IE 5.5+ and NS 6.0+

function Browser() {

  var ua, s, i;

  this.isIE    = false;
  this.isOP    = false;
  this.isNS    = false;
  this.version = null;

  ua = navigator.userAgent;

  s = "Opera";
  if ((i = ua.indexOf(s)) >= 0) {
    this.isOP = true;
    this.version = parseFloat(ua.substr(i + s.length));
    return;
  }

  s = "MSIE";
  if ((i = ua.indexOf(s)) >= 0) {
    this.isIE = true;
    this.version = parseFloat(ua.substr(i + s.length));
    return;
  }

  s = "Netscape6/";
  if ((i = ua.indexOf(s)) >= 0) {
    this.isNS = true;
    this.version = parseFloat(ua.substr(i + s.length));
    return;
  }

  // Treat any other "Gecko" browser as NS 6.1.

  s = "Gecko";
  if ((i = ua.indexOf(s)) >= 0) {
    this.isNS = true;
    this.version = 6.1;
    return;
  }
}

var browser = new Browser();

// Negate width setting on menu style rule for IE and NS. Width must be set
// in style rule for Opera.

if (browser.isIE)
  document.styleSheets[document.styleSheets.length - 1].addRule(".menu", "width:auto");
if (browser.isNS)
  document.styleSheets[document.styleSheets.length - 1].insertRule(".menu { width:auto; }", document.styleSheets[document.styleSheets.length - 1].cssRules.length);

// Global variable for tracking the currently active button.

var activeButton = null;

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

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

function pageMousedown(event) {

  var el;

  // If there is no active menu, exit.

  if (!activeButton)
    return;

  // Find the element that was clicked on.

  if (browser.isIE || browser.isOP)
    el = window.event.srcElement;
  if (browser.isNS)
    el = (event.target.className ? event.target : event.target.parentNode);

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

  if (el == activeButton)
    return;

  // If the element clicked on was not a menu button or item, close the
  // active menu.

  if (el.className != "menuButton"  && el.className != "menuItem"    &&
      el.className != "menuItemHdr" && el.className != "menuItemSep" &&
      el.className != "menu")
    resetButton(activeButton);
}

function buttonClick(button, menuName) {

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

  button.blur();

  // Associate the named menu to this button if not already done.

  if (!button.menu)
    button.menu = document.getElementById(menuName);

  // Reset the currently active button, if any.

  if (activeButton && activeButton != button)
    resetButton(activeButton);

  // Toggle the button's state.

  if (button.isDepressed)
    resetButton(button);
  else
    depressButton(button);

  return false;
}

function buttonMouseover(button, menuName) {

  // If any other button menu is active, deactivate it and activate this one.
  // Note: if this button has no menu, leave the active menu alone.

  if (activeButton && activeButton != button) {
    resetButton(activeButton);
    if (menuName)
      buttonClick(button, menuName);
  }
}

function depressButton(button) {

  var w, dw, x, y;

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

  button.className = "menuButtonActive";

  // For IE, set an explicit width on the first menu item. This will
  // cause link hovers to work on all the menu's items even when the
  // cursor is not over the link's text.

  if (browser.isIE && !button.menu.firstChild.style.width) {
    w = button.menu.firstChild.offsetWidth;
    button.menu.firstChild.style.width = w + "px";
    dw = button.menu.firstChild.offsetWidth - w;
    w -= dw;
    button.menu.firstChild.style.width = w + "px";
  }

  // Position the associated drop down menu under the button and
  // show it. Note that the position must be adjusted according to
  // browser, styling and positioning.

  x = getPageOffsetLeft(button);
  y = getPageOffsetTop(button) + button.offsetHeight;
  if (browser.isNS && browser.version < 6.1) {
    x--;
    y--;
  }

  // For Opera, need to use .pixelXXXX properties due to bug with
  // standard style properties.

  if (browser.isOP) {
    y = getPageOffsetTop(button) + button.style.pixelHeight + 1;
    button.menu.style.pixelLeft = x;
    button.menu.style.pixelTop  = y;
  }
  else {
    button.menu.style.left = x + "px";
    button.menu.style.top  = y + "px";
  }

  button.menu.style.visibility = "visible";

  // Set button state and let the world know which button is
  // active.

  button.isDepressed = true;
  activeButton = button;
}

function resetButton(button) {

  // Restore the button's style class.

  button.className = "menuButton";

  // Hide the button's menu.

  if (button.menu)
    button.menu.style.visibility = "hidden";

  // Set button state and clear active menu global.

  button.isDepressed = false;
  activeButton = null;
}

function getPageOffsetLeft(el) {

  // Return the true x coordinate of an element relative to the page.

  return el.offsetLeft + (el.offsetParent ? getPageOffsetLeft(el.offsetParent) : 0);
}

function getPageOffsetTop(el) {

  // Return the true y coordinate of an element relative to the page.

  return el.offsetTop + (el.offsetParent ? getPageOffsetTop(el.offsetParent) : 0);
}