// retrieve all elements of a given class
  function getElementsByClass(search)
  {
      var classElements = new Array();
      var els = document.getElementsByTagName('*');
      var pattern = new RegExp('(^|\\s)' + search + '(\\s|// mark a row as selected
  function selectTableRow(data, e)
  {
      unselectTableRow();
      e.type = e.className;
      e.className = 'selectedRow';
      window.filename = data;
  }
  
  // unselect row
  function unselectTableRow()
  {
      for (i = 0, s = getElementsByClass('selectedRow'); i < s.length; i++)
      {
          s[i].className = s[i].type;
      }
  
      hideForms();
  }
  
  // highlight a table row on mouseover
  function highlightTableRow(e)
  {
      if (e.className != 'selectedRow')
      {
          e.style.backgroundColor = '#C3C3FE';
      }
  }
  
  // remove the highlighting on mouseout
  function unhighlightTableRow(e)
  {
      e.style.backgroundColor = '';
  }
  
  // register event handlers and set initial view
  window.onload = function()
  {
      window.directory = '/';  // current directory viewed
      window.filename = '';    // currently selected file
  
      // event handlers
      document.getElementById('btn_open').onclick = openSelected;
  
      document.getElementById('btn_new_folder').onclick = showNewFolder;
      document.getElementById('form_new_submit').onclick = doNewFolder;
      document.getElementById('form_new_reset').onclick = hideForms;
  
      document.getElementById('btn_upload').onclick = showUploadFile;
      document.getElementById('form_upload').target = 'my_iframe';
      document.getElementById('form_upload_submit').onclick = doUploadFile;
      document.getElementById('form_upload_reset').onclick = hideForms;
  
      document.getElementById('btn_rename').onclick = showRename;
      document.getElementById('form_rename_submit').onclick = doRename;
      document.getElementById('form_rename_reset').onclick = hideForms;
  
      document.getElementById('btn_delete').onclick = doDelete;
  
      // load the file listing
      refreshFilesList();
  }
  
  // retrieve display of files and directories
  function refreshFilesList()
  {
      hideForms();
  
      var url = 'process.php?action=list&dir=' + window.directory + '&nocache=' +
          (new Date()).getTime();
  
      window.httpObj = createXMLHTTPObject();
      window.httpObj.open('GET', url , true);
  
      window.httpObj.onreadystatechange = function()
      {
          if (window.httpObj.readyState == 4 && window.httpObj.responseText)
          {
              // populate the fields
              document.getElementById('file_datagrid').innerHTML =
                  window.httpObj.responseText;
  
              window.filename = '';  // selected file
          }
      }
  
      window.httpObj.send(null);
  }
  
  // hide all input forms
  function hideForms()
  {
      document.getElementById('form_new').style.display = 'none';
      document.getElementById('form_rename').style.display = 'none';
      document.getElementById('form_upload').style.display = 'none';
  }
  
  // alert user the upload failed
  function uploadFailed()
  {
      alert('Failed to upload file.');
      hideForms();
  }
  
  // show form to upload a new file 
  function showUploadFile()
  {
      hideForms();
      document.getElementById('form_upload').reset();
      document.getElementById('form_upload').style.display = '';
  }
  
  // set form_upload_directory (allow browser to handle form
  // submission)
  function doUploadFile()
  {
      document.getElementById('form_upload_directory').value = window.directory;
  }
  
  // show form to create new folder
  function showNewFolder()
  {
      hideForms();
      document.getElementById('form_new_name').value = '';
      document.getElementById('form_new').style.display = '';
  }
  
  // create a new folder
  function doNewFolder()
  {
      var url = 'process.php?action=new&dir=' + window.directory + '&name=' +
          document.getElementById('form_new_name').value + '&nocache=' +
          (new Date()).getTime();
  
      window.httpObj = createXMLHTTPObject();
      window.httpObj.open('GET', url , true);
  
      window.httpObj.onreadystatechange = function()
      {
          if (window.httpObj.readyState == 4 && window.httpObj.responseText)
          {
              if (window.httpObj.responseText == 'OK')
              {
                  refreshFilesList();
              }
              else
              {
                  alert('Unable to create directory.');
              }
          }
      }
  
      window.httpObj.send(null);
      return false;
  }
  
  // show form to rename a file or directory
  function showRename()
  {
      // don't rename a parent directory or if no file is selected
      if (window.filename == '..' || window.filename == '')
      {
          return;
      }
  
      hideForms();
      document.getElementById('form_rename_name').value = window.filename;
      document.getElementById('form_rename').style.display = '';
  }
  
  // rename the file or directory
  function doRename()
  {
      var url = 'process.php?action=rename&dir=' + window.directory +
          '&oldfile=' + window.filename + '&newfile=' +
          document.getElementById('form_rename_name').value + '&nocache=' +
          (new Date()).getTime();
  
      window.httpObj = createXMLHTTPObject();
      window.httpObj.open('GET', url , true);
  
      window.httpObj.onreadystatechange = function()
      {
          if (window.httpObj.readyState == 4 && window.httpObj.responseText)
          {
              if (window.httpObj.responseText == 'OK')
              {
                  refreshFilesList();
              }
              else
              {
                  alert('Unable to rename entry.');
              }
          }
      }
  
      window.httpObj.send(null);
      return false;
  }
  
  // delete a directory or file
  function doDelete()
  {
      // don't delete a parent directory or if no file is selected
      if (window.filename == '..' || window.filename == '')
      {
          return;
      }
  
      if (!confirm('Are you sure you wish to delete?'))
      {
          return;
      }
  
      var url = 'process.php?action=delete&dir=' + window.directory + '&file=' +
          window.filename + '&nocache=' + (new Date()).getTime();
  
      window.httpObj = createXMLHTTPObject();
      window.httpObj.open('GET', url , true);
  
      window.httpObj.onreadystatechange = function()
      {
          if (window.httpObj.readyState == 4 && window.httpObj.responseText)
          {
              if (window.httpObj.responseText == 'OK')
              {
                  refreshFilesList();
              }
              else
              {
                  alert('Unable to delete entry.');
              }
          }
      }
  
      httpObj.send(null);
  }
  
  // download the selected file or traverse into the selected directory
  function openSelected()
  {
      var url = 'process.php?action=open&dir=' + window.directory + '&file=' +
          window.filename + '&nocache=' + (new Date()).getTime();
  
      window.httpObj = createXMLHTTPObject();
      window.httpObj.open('GET', url , true);
  
      window.httpObj.onreadystatechange = function()
      {
          if (window.httpObj.readyState == 4 && window.httpObj.responseText)
          {
              var result = eval('(' + window.httpObj.responseText + ')');
              if (result.retType == 'directory')
              {
                  window.directory = result.directory;
                  refreshFilesList();
              }
              else if (result.retType == 'file')
              {
                  window.location = 'download.php?&dir=' + window.directory +
                      '&file=' + window.filename + '&nocache=' +
                      (new Date()).getTime();
              }
              else
              {
                  alert('Unknown error.');
              }
          }
      }
  
      window.httpObj.send(null);
      return false;
  }