// Whether to use javascript caching or not
  var useCache = true;

  // assoc array of pages interval pollers
  var pagePollers = new Array();

  // the debug-mode history browser
  var histWin;

  // Array of visited pages - used for 'back' button
  var visited = new Array('');

  // Array of visited-visited pages (used for pages looked at using the 'back' button)
  var revisited = new Array();

  // Array of cached pages
  var pageCache = new Array();

  // deprecated vars used for handling user's hard-back button
  var lastPage;
  var preventedUnload = false;

  // initialise ajax objects as global @todo: use array
  var pageContentManager = false;
  var pageTitleManager   = false;


  /*
   * @desc   Debug function, could be removed from debug menu
   *         and instead intrinsic for admin users, or called
   *         by hooked back/forward controls
   *
   * @author Leo Brown
   *
   */
  function stopCaching(){
   useCache = false;
   //alert('Pages will no longer be cached.');
  }



  /*
   * @desc   Check if the user has hit enter on the search box
   *         if so, get the results from the search page with the
   *         relevant text value
   *
   * @author Leo Brown
   *
   */
  function checkEnter(box,e)
  {
   var characterCode
   if(e && e.which)
   {
    e=e
    characterCode = e.which
   }
   else
   {
    e = event
    characterCode = e.keyCode
   }
   if(characterCode == 13)
   {
    getPage('search.php?s='+box.value,'',true)
    return false;
   }
 }



 /*
  * @desc   Faux ajax back function, using array of previously
  *         (re-)visited pages
  * @author Leo Brown
  */

 function prevPage(){

  // Knock the first (current) page off the top
  //revisited.push( visited.pop() );
  visited.pop();

  // Check if the last is valid, if so navigate
  // note that this function should not be available
  // from the interface if there are no elements
  last = visited.pop();
  if(last != undefined){
   getPage(last,'',true);
  }

  // User backed right up?
  if (visited.length == 1){
   document.getElementById('backButton').style.visibility='hidden';
  }

 }



 /*
  *  @todo Make sensible :|
  *  @todo Not use SMC style comments :O
  *
  */ 
 function nextPage(){

  next = revisited.pop();
  if(next != undefined){
   getPage(next ,'',true);
  }

 }



 /* @desc   Central ajax controller to load the page content into the right place
  *         also controls some knock-on interface elements
  * @author Leo Brown
  * @param  page the new page (content)
  * @param  watermark string of a jpeg in /img/watermark
  * @param  dontRandomise (whether or not to pass a random get param)
  */
 function getPage(page,watermark,dontRandomise) {

    // remove hostname which javascript may have 'cleverly' entered
    page = page.replace(document.location.protocol, '');
    page = page.replace(document.location.host, '');

    // directory to our content
    page = 'content/' + page;

    // Get rid of any per page polling
    for (i in pagePollers){
     clearInterval(pagePollers[i]);
    }
    pagePollers = new Array();

    visited.push(page);
    //document.getElementById('backButton').style.visibility='visible';

    lastPage = page;

    // set the right watermark, if given
    if(watermark!=undefined){
     document.body.style.backgroundImage = 'url(/img/watermark/'+watermark+'.jpg)';
    }

    // use cache to get page, if poss
    if (useCache && pageCache[page]){
     document.getElementById('content').innerHTML = pageCache[page];
     parseScript(document.getElementById('content'));
     //try{init()} catch(e){}

     // Draw page title again
     getPageTitle(page);

     return;
    }

    var self = this;
    if (window.XMLHttpRequest) {
        self.pageContentManager = new XMLHttpRequest();
    }
    else if (window.ActiveXObject) {

        if ( ! self.pageContentManager ){
            self.pageContentManager = new ActiveXObject("Microsoft.XMLHTTP");
        }
    }
	//added rqst param to stop IE caching

    if (!dontRandomise){
     getString = page+'?randomSeed='+Math.random();
    }
    else{
     getString = page;
    }

    // General options

    // Get page content
    self.pageContentManager.abort();
    self.pageContentManager.open('GET', getString, true);
    self.pageContentManager.setRequestHeader('Content-Type', 'text/html');
    self.pageContentManager.onreadystatechange = function() {
        if (self.pageContentManager.readyState == 4) {
              document.getElementById('content').innerHTML = self.pageContentManager.responseText;
              parseScript(document.getElementById('content'));
              try{init()} catch(e){}
              getPageTitle(page);
              pageCache[page] = self.pageContentManager.responseText;
        }
    }
    self.pageContentManager.send('');
 }


 /*
  *
  * @desc   Script block post-parser for AJAX innerHTML response
  *         Can't believe this has to be made.
  * @author Leo Brown
  *
  */
 function parseScript( results )
 {
    var children = results.childNodes;
    var child;
    var index;

    for (index=0; index<children.length; ++index)
    {
        if (children[index].tagName && "SCRIPT"==children[index].tagName)
        {
            eval( children[index].innerHTML );
        }
    }
 }



 /*
  *
  * @desc   Makes a request to a GD PHP engine to get an image
  *         title for the page based on its <title> tag...
  * @author Leo Brown
  *
  */
 function getPageTitle(page){

    // Get page title
    var self = this;
    if (window.XMLHttpRequest) {
        self.pageTitleManager = new XMLHttpRequest();
    }
    else if (window.ActiveXObject) {

        if ( ! self.pageTitleManager ){
            self.pageTitleManager = new ActiveXObject("Microsoft.XMLHTTP");
        }
    }

    self.pageTitleManager.open('GET', '/system/getTitle.php?p='+page, true);
    self.pageTitleManager.setRequestHeader('Content-Type', 'text/html');
    self.pageTitleManager.onreadystatechange = function() {

        if (self.pageTitleManager.readyState == 4) {

              if(document.getElementById('pageTitle')){
                 document.getElementById('pageTitle').innerHTML = self.pageTitleManager.responseText;
               }
        }
    }
    self.pageTitleManager.send('');
 }



 /*
  * @desc   'Hardback' override function, to hook document.body.unload.
  *         designed to overcome the limitations of AJAX content
  *         such as browser 'back' buttons that will suprise users
  * @author Leo Brown
  *
  */ 
 function fauxBack(){
  if(!preventedUnload){

   // If there is no recorded movement, get current page
   if (visited.length < 2){

    alert('nowhere to go...');
    lastPage = '&allowBack=1';

   }
   else{

     visited.pop();
     lastPage = visited.pop();

   }

   //alert('Hooking page unload...');
   window.location.replace('/?page='+lastPage);
  }
  else{
   //alert('Not hooking page unload...');
  }
  return false;
 }



 /*
  *
  * @desc   Debug page history function
  * @author Leo Brown
  *
  */
 function showPageHistory(){

  // define the start of the history window content (could do this using a fixed file)
   var pageHistory =
   "<link rel=stylesheet href=/core.css>"+
   "<h3>Page History</h3><ol><li><a href=# onclick='opener.getPage(this.innerHTML);return false;'>" +
   visited.join("</a></li><li><a href=# onclick='opener.getPage(this.innerHTML);return false;'>");

  // Dont bother making another open() call, if we already have a reference
  // browsers seem unhappy reopening a window if we're resuing the object...
  // but if we use a new object and the same win ref, then the content is blank when reusing, but okay reloading

  //histWin=null;
  if(!histWin){
   try{
    histWin = window.open('about:blank','HistWindow','left='+(screen.width-250)+',width=220,height=600,scrollbars=1',true);
   }
   catch(e){}
  }

  // Great, MS dont yet support document.clear() - this is their suggested hack:
  histWin.document.write('');
  histWin.document.close();

  // Write the history window contents to the history browser and set focus
  histWin.document.write(pageHistory);
  histWin.focus();

 }


 /*
  *
  * @desc   Body keyboard hook, primarily for quick debug functions
  * @author Leo Brown
  *
  */
 function keyListener(){

//  alert(event.keyCode);

  var KEY_LEFTBRACKET  = 91;
  var KEY_RIGHTBRACKET = 93;
  var KEY_NUMPAD5 = 53;

  switch(event.keyCode){

  case KEY_LEFTBRACKET:
   prevPage();
   break;

  case KEY_RIGHTBRACKET:
   nextPage();
   break;

   case KEY_NUMPAD5:
    getPage(visited[visited.length-1]);
    break;
  }

 }

 /*
  *
  * @desc   Create a new blank page showing the content from the main display area
  * @author Leo Brown, Elwood Casey
  *
  */
 function debugContent()
 {
   win = window.open('about:blank');
   win.document.write('<link rel="stylesheet" href="/core.css"></link>');
   win.document.write(document.getElementById('content').innerHTML);
 }


 // deprecated page body load fn - pls grep for usage
 function loadPage(page,watermark){
   document.getElementById('content').innerHTML = page;
   document.body.style.backgroundImage = 'url(/img/watermark/'+watermark+'.jpg)';
 }