// An inefficient, but effective bubble sort
var xmlpath   = 'http://elwood.mcom.com/bobclary/arun/';
var enabled = true;
var sortableProps = new Array('Author', 'Title', 'ISBN');
var i;
var xmlhttpBook;
// We uppercase the tagName as a workaround for a bug
// that loses the original case of the tag.
//Create an XMLHttpRequest Object on both browsers
if(document.all)
  xmlhttpBook = new ActiveXObject('MSXML2.XMLHTTP');
else
  xmlhttpBook = new XMLHttpRequest();
searchBooks();
function sort(key)
{
  var bookNodeList = document.getElementsByTagName('Book');
  // We need to create a 'non-live' array to operate on. Since
  // we'll be moving things around in this array, we can't use
  // the read-only, live one returned by getElementsByTagName.
  var bookArray = new Array();
  for (i = 0; i < bookNodeList.length; i++) 
    bookArray[i] = bookNodeList[i];
  collectInfo(bookArray, sortableProps);
  var i, j;
  var count = bookArray.length;
  var parent, child;
  for (i = count-1; i>= 0; i--)
  {
    for (j = 1; j <= i; j++)
    {
      if (bookArray[j-1][key] > bookArray[j][key])
      {
        // Move the item both in the local array and
        // in the tree
        child = bookArray[j];
        parent = child.parentNode;
        bookArray[j] = bookArray[j-1];
        bookArray[j-1] = child;
        parent.removeChild(child);
        parent.insertBefore(child, bookArray[j]);
      }
    }
  }
}
// Set user properties on the nodes in the collection
// based on information found in its children. For example,
// make a property 'Author' based on the content of the
// 'Author' element found in the childNode list of the node.
// This makes later sorting more efficient
function collectInfo(nodes, propNames)
{
  var i, j, k;
  var ncount = nodes.length;
  var pcount = propNames.length;
  for (i = 0; i < ncount; i++)
  {
    var node = nodes[i];
    var childNodes = node.childNodes;
    var ccount = childNodes.length;
    for (j = 0; j < ccount; j++)
    {
      var child = childNodes[j];
      if (document.all)
      {
        var tagName = child.tagName;
        for (k = 0; k < pcount; k++)
        {
          var prop = propNames[k];
          if (prop == tagName)
          {
            node[prop] = child.firstChild.data;
          }
        }
      }
      else if (child.nodeType == Node.ELEMENT_NODE)
      {
        var tagName = child.tagName;
        for (k = 0; k < pcount; k++)
        {
          var prop = propNames[k];
          if (prop == tagName)
          {
            node[prop] = child.firstChild.data;
          }
        }
      }
    }
  }
}
function toggleStyleSheet()
{
  document.styleSheets[2].disabled = enabled;
  enabled = !enabled;
}
// XXX This is a workaround for a bug where
// changing the disabled state of a stylesheet can't
// be done in an event handler. For now, we do it
// in a zero-delay timeout.
function initiateToggle()
{
  setTimeout(toggleStyleSheet, 0);
}
function searchBooks()
{
  var selection = document.getElementById('toggleBooks').value;
  var path = xmlpath + selection;
  var searchBookSet = document.getElementsByTagName('BookSet')[0];
  // Direct string inequality -- optimise later!
  if (document.all)
  {
    xmlhttpBook.Open('GET', path, false);
    xmlhttpBook.Send(null);
  }
  else 
  {
    xmlhttpBook.open('GET', path, false);
    xmlhttpBook.send(null);
  }
  var xmlResponse = xmlhttpBook.responseXML;
  if (!xmlResponse.documentElement)
    alert('Sorry, the request could not get through to the server');
  else
  {
    var resultBookSet = xmlResponse.getElementsByTagName('BookSet')[0];
    var importedBookSet = document.importNode(resultBookSet, true);
    searchBookSet.parentNode.replaceChild(importedBookSet, searchBookSet);
  }
}