/**
 * landgate_dynamic.js
 * 
 * JavaScript functions for Landgate corporate website pages requiring dynamic
 * expansion and contraction (display and undisplay) of page elements.
 */
/**
 * Determine whether the specified item is open.
 * @param elem DOM element to test.
 * @return True if the item is open, or false if it is closed.
 */
function isItemOpen(elem) {
  if (elem !== null && typeof(elem) !== 'undefined') {
    return elem.style.display === 'block';
  } else {
    return false;
  }
}
/**
 * Open the specified item.
 * @param elem DOM element to manipulate.
 */
function openItem(elem) {
  if (elem !== null && typeof(elem) !== 'undefined') {
    elem.style.display = 'block';
  }
}
/**
 * Open all items of the specified element type (tag name) and class.
 * 
 * @param className Value to look for in the class attribute.
 * @param tagName Name of the tags to manipulate.  Defaults to 'div'.
 */
function openAllItems(className, tagName) {
  if (!tagName) {
    tagName = 'div';
  }
  var ar = document.getElementsByTagName(tagName); 
  for (var i=0; i<ar.length; i++) {
    if (ar[i].className == className) {
      ar[i].style.display = 'block';
    }
  }
}
/**
 * Close the specified item.
 * @param elem DOM element to manipulate.
 */
function closeItem(elem) {
  if (elem !== null && typeof(elem) !== 'undefined') {
    elem.style.display = 'none';
  }
}
/**
 * Close all items of the specified element type (tag name) and class.
 * 
 * @param className Value to look for in the class attribute.
 * @param tagName Name of the tags to manipulate.  Defaults to 'div'.
 */
function closeAllItems(className, tagName) {
  if (!tagName) {
    tagName = 'div';
  }
  var ar = document.getElementsByTagName(tagName); 
  for (var i=0; i<ar.length; i++) {
    if (ar[i].className==className) {
      ar[i].style.display = 'none';
    }
  }
}
/**
 * Toggle the specified menu item between open and closed.
 */
function toggleItem(elem) {
  if (elem !== null && typeof(elem) !== 'undefined') {
    if (isItemOpen(elem)) {
      closeItem(elem);
    } else {
      openItem(elem);
    }
  }
}
/**
 * Set up the submenu when page is first loaded, by expanding and highlighting
 * the relevant components.
 */
function initialiseNavigation(currentSectionMenuID, sectionEntryUrl) {
  if (currentSectionMenuID && typeof(currentSectionMenuID) !== 'undefined') {
    // Expand the relevant submenu.
    if (document.getElementById && currentSectionMenuID !== '') {
      var sectionDiv = document.getElementById(currentSectionMenuID);
      if (sectionDiv && typeof(sectionDiv) !== 'undefined' && sectionDiv.style && typeof(sectionDiv.style) !== 'undefined') {
        sectionDiv.style.display = 'block';
      }
    }
  }
  // Fix URLs.
  var currentPageUrl = document.location.href.toLowerCase().replace(/^(.*)\#$/, "$1");
  sectionEntryUrl = sectionEntryUrl.toLowerCase().replace(/^(.*)\#$/, "$1");
  // Highlight the currently selected section link in top navigation.
  var mainNav = document.getElementById('mainNav');
  var mainNavLinks = mainNav.getElementsByTagName('a');
  for (var i=0; i<mainNavLinks.length; i++) {
    var href = mainNavLinks[i].getAttribute("href").toLowerCase();
    var index = href.indexOf(sectionEntryUrl);
    if (index >= 0 && index == href.length - sectionEntryUrl.length) {
      mainNavLinks[i].className = 'selected';
    }
  }
  // Highlight the currently selected link in side navigation.
  var sideNav = document.getElementById('sideNav');
  var sideNavLinks = sideNav.getElementsByTagName('a');
  for (var j=0; j<sideNavLinks.length; j++) {
    var href = sideNavLinks[j].getAttribute("href").toLowerCase();
    var index = currentPageUrl.indexOf(href);
    if (index >= 0 && index == currentPageUrl.length - href.length) {
      sideNavLinks[j].className = 'selected';
    }
  }
}
/**
 * Show the selected submenu and the current section submenu, hiding all others.
 */
function switchSubMenu(menuID, currentSectionMenuID, className) {
  closeAllItems(className);
  openItem(document.getElementById(menuID));
  openItem(document.getElementById(currentSectionMenuID));
}
/**
 * Show the current section submenu only, hiding all others.
 */
function resetMenu(currentSectionMenuID, className) {
  closeAllItems(className);
  if (currentSectionMenuID !== '') {
    openItem(document.getElementById(currentSectionMenuID));
  }
}
/**
 * Call this method to prevent propagation of the event e in a cross-browser 
 * manner.
 *
 * @param e Event to block.  For IE, this will be ignored and window.event 
 *   will be used instead.
 */
function blockEvent(e) {
  if (!e) var e = window.event;
  e.cancelBubble = true;
  if (e.stopPropagation) e.stopPropagation();
}