Club Drupal

(function ($) {

/**

 * Drag and drop table rows with field manipulation.

 *

 * Using the drupal_add_tabledrag() function, any table with weights or parent

 * relationships may be made into draggable tables. Columns containing a field

 * may optionally be hidden, providing a better user experience.

 *

 * Created tableDrag instances may be modified with custom behaviors by

 * overriding the .onDrag, .onDrop, .row.onSwap, and .row.onIndent methods.

 * See blocks.js for an example of adding additional functionality to tableDrag.

 */

Drupal.behaviors.tableDrag = {

  attach: function (context, settings) {

    for (var base in settings.tableDrag) {

      $('#' + base, context).once('tabledrag', function () {

        // Create the new tableDrag instance. Save in the Drupal variable

        // to allow other scripts access to the object.

        Drupal.tableDrag[base] = new Drupal.tableDrag(this, settings.tableDrag[base]);

      });

    }

  }

};

/**

 * Constructor for the tableDrag object. Provides table and field manipulation.

 *

 * @param table

 *   DOM object for the table to be made draggable.

 * @param tableSettings

 *   Settings for the table added via drupal_add_dragtable().

 */

Drupal.tableDrag = function (table, tableSettings) {

  var self = this;

  // Required object variables.

  this.table = table;

  this.tableSettings = tableSettings;

  this.dragObject = null; // Used to hold information about a current drag operation.

  this.rowObject = null; // Provides operations for row manipulation.

  this.oldRowElement = null; // Remember the previous element.

  this.oldY = 0; // Used to determine up or down direction from last mouse move.

  this.changed = false; // Whether anything in the entire table has changed.

  this.maxDepth = 0; // Maximum amount of allowed parenting.

  this.rtl = $(this.table).css('direction') == 'rtl' ? -1 : 1; // Direction of the table.

  // Configure the scroll settings.

  this.scrollSettings = { amount: 4, interval: 50, trigger: 70 };

  this.scrollInterval = null;

  this.scrollY = 0;

  this.windowHeight = 0;

  // Check this table's settings to see if there are parent relationships in

  // this table. For efficiency, large sections of code can be skipped if we

  // don't need to track horizontal movement and indentations.

  this.indentEnabled = false;

  for (var group in tableSettings) {

    for (var n in tableSettings[group]) {

      if (tableSettings[group][n].relationship == 'parent') {

        this.indentEnabled = true;

      }

      if (tableSettings[group][n].limit > 0) {

        this.maxDepth = tableSettings[group][n].limit;

      }

    }

  }

  if (this.indentEnabled) {

    this.indentCount = 1; // Total width of indents, set in makeDraggable.

    // Find the width of indentations to measure mouse movements against.

    // Because the table doesn't need to start with any indentations, we

    // manually append 2 indentations in the first draggable row, measure

    // the offset, then remove.

    var indent = Drupal.theme('tableDragIndentation');

    var testRow = $('<tr/>').addClass('draggable').appendTo(table);

    var testCell = $('<td/>').appendTo(testRow).prepend(indent).prepend(indent);

    this.indentAmount = $('.indentation', testCell).get(1).offsetLeft - $('.indentation', testCell).get(0).offsetLeft;

    testRow.remove();

  }

  // Make each applicable row draggable.

  // Match immediate children of the parent element to allow nesting.

  $('> tr.draggable, > tbody > tr.draggable', table).each(function () { self.makeDraggable(this); });

  // Add a link before the table for users to show or hide weight columns.

  $(table).before($('<a href="#" class="tabledrag-toggle-weight"></a>')

    .attr('title', Drupal.t('Re-order rows by numerical weight instead of dragging.'))

    .click(function () {

      if ($.cookie('Drupal.tableDrag.showWeight') == 1) {

        self.hideColumns();

      }

      else {

        self.showColumns();

      }

      return false;

    })

    .wrap('<div class="tabledrag-toggle-weight-wrapper"></div>')

    .parent()

  );

  // Initialize the specified columns (for example, weight or parent columns)

  // to show or hide according to user preference. This aids accessibility

  // so that, e.g., screen reader users can choose to enter weight values and

  // manipulate form elements directly, rather than using drag-and-drop..

  self.initColumns();

  // Add mouse bindings to the document. The self variable is passed along

  // as event handlers do not have direct access to the tableDrag object.

  $(document).bind('mousemove pointermove', function (event) { return self.dragRow(event, self); });

  $(document).bind('mouseup pointerup', function (event) { return self.dropRow(event, self); });

  $(document).bind('touchmove', function (event) { return self.dragRow(event.originalEvent.touches[0], self); });

  $(document).bind('touchend', function (event) { return self.dropRow(event.originalEvent.touches[0], self); });

};

/**

 * Initialize columns containing form elements to be hidden by default,

 * according to the settings for this tableDrag instance.

 *

 * Identify and mark each cell with a CSS class so we can easily toggle

 * show/hide it. Finally, hide columns if user does not have a

 * 'Drupal.tableDrag.showWeight' cookie.

 */

Drupal.tableDrag.prototype.initColumns = function () {

  for (var group in this.tableSettings) {

    // Find the first field in this group.

    for (var d in this.tableSettings[group]) {

      var field = $('.' + this.tableSettings[group][d].target + ':first', this.table);

      if (field.length && this.tableSettings[group][d].hidden) {

        var hidden = this.tableSettings[group][d].hidden;

        var cell = field.closest('td');

        break;

      }

    }

    // Mark the column containing this field so it can be hidden.

    if (hidden && cell[0]) {

      // Add 1 to our indexes. The nth-child selector is 1 based, not 0 based.

      // Match immediate children of the parent element to allow nesting.

      var columnIndex = $('> td', cell.parent()).index(cell.get(0)) + 1;

      $('> thead > tr, > tbody > tr, > tr', this.table).each(function () {

        // Get the columnIndex and adjust for any colspans in this row.

        var index = columnIndex;

        var cells = $(this).children();

        cells.each(function (n) {

          if (n < index && this.colSpan && this.colSpan > 1) {

            index -= this.colSpan - 1;

          }

        });

        if (index > 0) {

          cell = cells.filter(':nth-child(' + index + ')');

          if (cell[0].colSpan && cell[0].colSpan > 1) {

            // If this cell has a colspan, mark it so we can reduce the colspan.

            cell.addClass('tabledrag-has-colspan');

          }

          else {

            // Mark this cell so we can hide it.

            cell.addClass('tabledrag-hide');

          }

        }

      });

    }

  }

  // Now hide cells and reduce colspans unless cookie indicates previous choice.

  // Set a cookie if it is not already present.

  if ($.cookie('Drupal.tableDrag.showWeight') === null) {

    $.cookie('Drupal.tableDrag.showWeight', 0, {

      path: Drupal.settings.basePath,

      // The cookie expires in one year.

      expires: 365

    });

    this.hideColumns();

  }

  // Check cookie value and show/hide weight columns accordingly.

  else {

    if ($.cookie('Drupal.tableDrag.showWeight') == 1) {

      this.showColumns();

    }

    else {

      this.hideColumns();

    }

  }

};

/**

 * Hide the columns containing weight/parent form elements.

 * Undo showColumns().

 */

Drupal.tableDrag.prototype.hideColumns = function () {

  // Hide weight/parent cells and headers.

  $('.tabledrag-hide', 'table.tabledrag-processed').css('display', 'none');

  // Show TableDrag handles.

  $('.tabledrag-handle', 'table.tabledrag-processed').css('display', '');

  // Reduce the colspan of any effected multi-span columns.

  $('.tabledrag-has-colspan', 'table.tabledrag-processed').each(function () {

    this.colSpan = this.colSpan - 1;

  });

  // Change link text.

  $('.tabledrag-toggle-weight').text(Drupal.t('Show row weights'));

  // Change cookie.

  $.cookie('Drupal.tableDrag.showWeight', 0, {

    path: Drupal.settings.basePath,

    // The cookie expires in one year.

    expires: 365

  });

  // Trigger an event to allow other scripts to react to this display change.

  $('table.tabledrag-processed').trigger('columnschange', 'hide');

};

/**

 * Show the columns containing weight/parent form elements

 * Undo hideColumns().

 */

Drupal.tableDrag.prototype.showColumns = function () {

  // Show weight/parent cells and headers.

  $('.tabledrag-hide', 'table.tabledrag-processed').css('display', '');

  // Hide TableDrag handles.

  $('.tabledrag-handle', 'table.tabledrag-processed').css('display', 'none');

  // Increase the colspan for any columns where it was previously reduced.

  $('.tabledrag-has-colspan', 'table.tabledrag-processed').each(function () {

    this.colSpan = this.colSpan + 1;

  });

  // Change link text.

  $('.tabledrag-toggle-weight').text(Drupal.t('Hide row weights'));

  // Change cookie.

  $.cookie('Drupal.tableDrag.showWeight', 1, {

    path: Drupal.settings.basePath,

    // The cookie expires in one year.

    expires: 365

  });

  // Trigger an event to allow other scripts to react to this display change.

  $('table.tabledrag-processed').trigger('columnschange', 'show');

};

/**

 * Find the target used within a particular row and group.

 */

Drupal.tableDrag.prototype.rowSettings = function (group, row) {

  var field = $('.' + group, row);

  for (var delta in this.tableSettings[group]) {

    var targetClass = this.tableSettings[group][delta].target;

    if (field.is('.' + targetClass)) {

      // Return a copy of the row settings.

      var rowSettings = {};

      for (var n in this.tableSettings[group][delta]) {

        rowSettings[n] = this.tableSettings[group][delta][n];

      }

      return rowSettings;

    }

  }

};

/**

 * Take an item and add event handlers to make it become draggable.

 */

Drupal.tableDrag.prototype.makeDraggable = function (item) {

  var self = this;

  // Create the handle.

  var handle = $('<a href="#" class="tabledrag-handle"><div class="handle">&nbsp;</div></a>').attr('title', Drupal.t('Drag to re-order'));

  // Insert the handle after indentations (if any).

  if ($('td:first .indentation:last', item).length) {

    $('td:first .indentation:last', item).after(handle);

    // Update the total width of indentation in this entire table.

    self.indentCount = Math.max($('.indentation', item).length, self.indentCount);

  }

  else {

    $('td:first', item).prepend(handle);

  }

  // Add hover action for the handle.

  handle.hover(function () {

    self.dragObject == null ? $(this).addClass('tabledrag-handle-hover') : null;

  }, function () {

    self.dragObject == null ? $(this).removeClass('tabledrag-handle-hover') : null;

  });

  // Add the mousedown action for the handle.

  handle.bind('mousedown touchstart pointerdown', function (event) {

    if (event.originalEvent.type == "touchstart") {

      event = event.originalEvent.touches[0];

    }

    // Create a new dragObject recording the event information.

    self.dragObject = {};

    self.dragObject.initMouseOffset = self.getMouseOffset(item, event);

    self.dragObject.initMouseCoords = self.mouseCoords(event);

    if (self.indentEnabled) {

      self.dragObject.indentMousePos = self.dragObject.initMouseCoords;

    }

    // If there's a lingering row object from the keyboard, remove its focus.

    if (self.rowObject) {

      $('a.tabledrag-handle', self.rowObject.element).blur();

    }

    // Create a new rowObject for manipulation of this row.

    self.rowObject = new self.row(item, 'mouse', self.indentEnabled, self.maxDepth, true);

    // Save the position of the table.

    self.table.topY = $(self.table).offset().top;

    self.table.bottomY = self.table.topY + self.table.offsetHeight;

    // Add classes to the handle and row.

    $(this).addClass('tabledrag-handle-hover');

    $(item).addClass('drag');

    // Set the document to use the move cursor during drag.

    $('body').addClass('drag');

    if (self.oldRowElement) {

      $(self.oldRowElement).removeClass('drag-previous');

    }

    // Hack for IE6 that flickers uncontrollably if select lists are moved.

    if (navigator.userAgent.indexOf('MSIE 6.') != -1) {

      $('select', this.table).css('display', 'none');

    }

    // Hack for Konqueror, prevent the blur handler from firing.

    // Konqueror always gives links focus, even after returning false on mousedown.

    self.safeBlur = false;

    // Call optional placeholder function.

    self.onDrag();

    return false;

  });

  // Prevent the anchor tag from jumping us to the top of the page.

  handle.click(function () {

    return false;

  });

  // Similar to the hover event, add a class when the handle is focused.

  handle.focus(function () {

    $(this).addClass('tabledrag-handle-hover');

    self.safeBlur = true;

  });

  // Remove the handle class on blur and fire the same function as a mouseup.

  handle.blur(function (event) {

    $(this).removeClass('tabledrag-handle-hover');

    if (self.rowObject && self.safeBlur) {

      self.dropRow(event, self);

    }

  });

  // Add arrow-key support to the handle.

  handle.keydown(function (event) {

    // If a rowObject doesn't yet exist and this isn't the tab key.

    if (event.keyCode != 9 && !self.rowObject) {

      self.rowObject = new self.row(item, 'keyboard', self.indentEnabled, self.maxDepth, true);

    }

    var keyChange = false;

    switch (event.keyCode) {

      case 37: // Left arrow.

      case 63234: // Safari left arrow.

        keyChange = true;

        self.rowObject.indent(-1 * self.rtl);

        break;

      case 38: // Up arrow.

      case 63232: // Safari up arrow.

        var previousRow = $(self.rowObject.element).prev('tr').get(0);

        while (previousRow && $(previousRow).is(':hidden')) {

          previousRow = $(previousRow).prev('tr').get(0);

        }

        if (previousRow) {

          self.safeBlur = false; // Do not allow the onBlur cleanup.

          self.rowObject.direction = 'up';

          keyChange = true;

          if ($(item).is('.tabledrag-root')) {

            // Swap with the previous top-level row.

            var groupHeight = 0;

            while (previousRow && $('.indentation', previousRow).length) {

              previousRow = $(previousRow).prev('tr').get(0);

              groupHeight += $(previousRow).is(':hidden') ? 0 : previousRow.offsetHeight;

            }

            if (previousRow) {

              self.rowObject.swap('before', previousRow);

              // No need to check for indentation, 0 is the only valid one.

              window.scrollBy(0, -groupHeight);

            }

          }

          else if (self.table.tBodies[0].rows[0] != previousRow || $(previousRow).is('.draggable')) {

            // Swap with the previous row (unless previous row is the first one

            // and undraggable).

            self.rowObject.swap('before', previousRow);

            self.rowObject.interval = null;

            self.rowObject.indent(0);

            window.scrollBy(0, -parseInt(item.offsetHeight, 10));

          }

          handle.get(0).focus(); // Regain focus after the DOM manipulation.

        }

        break;

      case 39: // Right arrow.

      case 63235: // Safari right arrow.

        keyChange = true;

        self.rowObject.indent(1 * self.rtl);

        break;

      case 40: // Down arrow.

      case 63233: // Safari down arrow.

        var nextRow = $(self.rowObject.group).filter(':last').next('tr').get(0);

        while (nextRow && $(nextRow).is(':hidden')) {

          nextRow = $(nextRow).next('tr').get(0);

        }

        if (nextRow) {

          self.safeBlur = false; // Do not allow the onBlur cleanup.

          self.rowObject.direction = 'down';

          keyChange = true;

          if ($(item).is('.tabledrag-root')) {

            // Swap with the next group (necessarily a top-level one).

            var groupHeight = 0;

            var nextGroup = new self.row(nextRow, 'keyboard', self.indentEnabled, self.maxDepth, false);

            if (nextGroup) {

              $(nextGroup.group).each(function () {

                groupHeight += $(this).is(':hidden') ? 0 : this.offsetHeight;

              });

              var nextGroupRow = $(nextGroup.group).filter(':last').get(0);

              self.rowObject.swap('after', nextGroupRow);

              // No need to check for indentation, 0 is the only valid one.

              window.scrollBy(0, parseInt(groupHeight, 10));

            }

          }

          else {

            // Swap with the next row.

            self.rowObject.swap('after', nextRow);

            self.rowObject.interval = null;

            self.rowObject.indent(0);

            window.scrollBy(0, parseInt(item.offsetHeight, 10));

          }

          handle.get(0).focus(); // Regain focus after the DOM manipulation.

        }

        break;

    }

    if (self.rowObject && self.rowObject.changed == true) {

      $(item).addClass('drag');

      if (self.oldRowElement) {

        $(self.oldRowElement).removeClass('drag-previous');

      }

      self.oldRowElement = item;

      self.restripeTable();

      self.onDrag();

    }

    // Returning false if we have an arrow key to prevent scrolling.

    if (keyChange) {

      return false;

    }

  });

  // Compatibility addition, return false on keypress to prevent unwanted scrolling.

  // IE and Safari will suppress scrolling on keydown, but all other browsers

  // need to return false on keypress. http://www.quirksmode.org/js/keys.html

  handle.keypress(function (event) {

    switch (event.keyCode) {

      case 37: // Left arrow.

      case 38: // Up arrow.

      case 39: // Right arrow.

      case 40: // Down arrow.

        return false;

    }

  });

};

/**

 * Mousemove event handler, bound to document.

 */

Drupal.tableDrag.prototype.dragRow = function (event, self) {

  if (self.dragObject) {

    self.currentMouseCoords = self.mouseCoords(event);

    var y = self.currentMouseCoords.y - self.dragObject.initMouseOffset.y;

    var x = self.currentMouseCoords.x - self.dragObject.initMouseOffset.x;

    // Check for row swapping and vertical scrolling.

    if (y != self.oldY) {

      self.rowObject.direction = y > self.oldY ? 'down' : 'up';

      self.oldY = y; // Update the old value.

      // Check if the window should be scrolled (and how fast).

      var scrollAmount = self.checkScroll(self.currentMouseCoords.y);

      // Stop any current scrolling.

      clearInterval(self.scrollInterval);

      // Continue scrolling if the mouse has moved in the scroll direction.

      if (scrollAmount > 0 && self.rowObject.direction == 'down' || scrollAmount < 0 && self.rowObject.direction == 'up') {

        self.setScroll(scrollAmount);

      }

      // If we have a valid target, perform the swap and restripe the table.

      var currentRow = self.findDropTargetRow(x, y);

      if (currentRow) {

        if (self.rowObject.direction == 'down') {

          self.rowObject.swap('after', currentRow, self);

        }

        else {

          self.rowObject.swap('before', currentRow, self);

        }

        self.restripeTable();

      }

    }

    // Similar to row swapping, handle indentations.

    if (self.indentEnabled) {

      var xDiff = self.currentMouseCoords.x - self.dragObject.indentMousePos.x;

      // Set the number of indentations the mouse has been moved left or right.

      var indentDiff = Math.round(xDiff / self.indentAmount);

      // Indent the row with our estimated diff, which may be further

      // restricted according to the rows around this row.

      var indentChange = self.rowObject.indent(indentDiff);

      // Update table and mouse indentations.

      self.dragObject.indentMousePos.x += self.indentAmount * indentChange * self.rtl;

      self.indentCount = Math.max(self.indentCount, self.rowObject.indents);

    }

    return false;

  }

};

/**

 * Mouseup event handler, bound to document.

 * Blur event handler, bound to drag handle for keyboard support.

 */

Drupal.tableDrag.prototype.dropRow = function (event, self) {

  // Drop row functionality shared between mouseup and blur events.

  if (self.rowObject != null) {

    var droppedRow = self.rowObject.element;

    // The row is already in the right place so we just release it.

    if (self.rowObject.changed == true) {

      // Update the fields in the dropped row.

      self.updateFields(droppedRow);

      // If a setting exists for affecting the entire group, update all the

      // fields in the entire dragged group.

      for (var group in self.tableSettings) {

        var rowSettings = self.rowSettings(group, droppedRow);

        if (rowSettings.relationship == 'group') {

          for (var n in self.rowObject.children) {

            self.updateField(self.rowObject.children[n], group);

          }

        }

      }

      self.rowObject.markChanged();

      if (self.changed == false) {

        $(Drupal.theme('tableDragChangedWarning')).insertBefore(self.table).hide().fadeIn('slow');

        self.changed = true;

      }

    }

    if (self.indentEnabled) {

      self.rowObject.removeIndentClasses();

    }

    if (self.oldRowElement) {

      $(self.oldRowElement).removeClass('drag-previous');

    }

    $(droppedRow).removeClass('drag').addClass('drag-previous');

    self.oldRowElement = droppedRow;

    self.onDrop();

    self.rowObject = null;

  }

  // Functionality specific only to mouseup event.

  if (self.dragObject != null) {

    $('.tabledrag-handle', droppedRow).removeClass('tabledrag-handle-hover');

    self.dragObject = null;

    $('body').removeClass('drag');

    clearInterval(self.scrollInterval);

    // Hack for IE6 that flickers uncontrollably if select lists are moved.

    if (navigator.userAgent.indexOf('MSIE 6.') != -1) {

      $('select', this.table).css('display', 'block');

    }

  }

};

/**

 * Get the mouse coordinates from the event (allowing for browser differences).

 */

Drupal.tableDrag.prototype.mouseCoords = function (event) {

  // Complete support for pointer events was only introduced to jQuery in

  // version 1.11.1; between versions 1.7 and 1.11.0 pointer events have the

  // clientX and clientY properties undefined. In those cases, the properties

  // must be retrieved from the event.originalEvent object instead.

  var clientX = event.clientX || event.originalEvent.clientX;

  var clientY = event.clientY || event.originalEvent.clientY;

  if (event.pageX || event.pageY) {

    return { x: event.pageX, y: event.pageY };

  }

  return {

    x: clientX + document.body.scrollLeft - document.body.clientLeft,

    y: clientY + document.body.scrollTop  - document.body.clientTop

  };

};

/**

 * Given a target element and a mouse event, get the mouse offset from that

 * element. To do this we need the element's position and the mouse position.

 */

Drupal.tableDrag.prototype.getMouseOffset = function (target, event) {

  var docPos   = $(target).offset();

  var mousePos = this.mouseCoords(event);

  return { x: mousePos.x - docPos.left, y: mousePos.y - docPos.top };

};

/**

 * Find the row the mouse is currently over. This row is then taken and swapped

 * with the one being dragged.

 *

 * @param x

 *   The x coordinate of the mouse on the page (not the screen).

 * @param y

 *   The y coordinate of the mouse on the page (not the screen).

 */

Drupal.tableDrag.prototype.findDropTargetRow = function (x, y) {

  var rows = $(this.table.tBodies[0].rows).not(':hidden');

  for (var n = 0; n < rows.length; n++) {

    var row = rows[n];

    var indentDiff = 0;

    var rowY = $(row).offset().top;

    // Because Safari does not report offsetHeight on table rows, but does on

    // table cells, grab the firstChild of the row and use that instead.

    // http://jacob.peargrove.com/blog/2006/technical/table-row-offsettop-bug-in-safari.

    if (row.offsetHeight == 0) {

      var rowHeight = parseInt(row.firstChild.offsetHeight, 10) / 2;

    }

    // Other browsers.

    else {

      var rowHeight = parseInt(row.offsetHeight, 10) / 2;

    }

    // Because we always insert before, we need to offset the height a bit.

    if ((y > (rowY - rowHeight)) && (y < (rowY + rowHeight))) {

      if (this.indentEnabled) {

        // Check that this row is not a child of the row being dragged.

        for (var n in this.rowObject.group) {

          if (this.rowObject.group[n] == row) {

            return null;

          }

        }

      }

      else {

        // Do not allow a row to be swapped with itself.

        if (row == this.rowObject.element) {

          return null;

        }

      }

      // Check that swapping with this row is allowed.

      if (!this.rowObject.isValidSwap(row)) {

        return null;

      }

      // We may have found the row the mouse just passed over, but it doesn't

      // take into account hidden rows. Skip backwards until we find a draggable

      // row.

      while ($(row).is(':hidden') && $(row).prev('tr').is(':hidden')) {

        row = $(row).prev('tr').get(0);

      }

      return row;

    }

  }

  return null;

};

/**

 * After the row is dropped, update the table fields according to the settings

 * set for this table.

 *

 * @param changedRow

 *   DOM object for the row that was just dropped.

 */

Drupal.tableDrag.prototype.updateFields = function (changedRow) {

  for (var group in this.tableSettings) {

    // Each group may have a different setting for relationship, so we find

    // the source rows for each separately.

    this.updateField(changedRow, group);

  }

};

/**

 * After the row is dropped, update a single table field according to specific

 * settings.

 *

 * @param changedRow

 *   DOM object for the row that was just dropped.

 * @param group

 *   The settings group on which field updates will occur.

 */

Drupal.tableDrag.prototype.updateField = function (changedRow, group) {

  var rowSettings = this.rowSettings(group, changedRow);

  // Set the row as its own target.

  if (rowSettings.relationship == 'self' || rowSettings.relationship == 'group') {

    var sourceRow = changedRow;

  }

  // Siblings are easy, check previous and next rows.

  else if (rowSettings.relationship == 'sibling') {

    var previousRow = $(changedRow).prev('tr').get(0);

    var nextRow = $(changedRow).next('tr').get(0);

    var sourceRow = changedRow;

    if ($(previousRow).is('.draggable') && $('.' + group, previousRow).length) {

      if (this.indentEnabled) {

        if ($('.indentations', previousRow).length == $('.indentations', changedRow)) {

          sourceRow = previousRow;

        }

      }

      else {

        sourceRow = previousRow;

      }

    }

    else if ($(nextRow).is('.draggable') && $('.' + group, nextRow).length) {

      if (this.indentEnabled) {

        if ($('.indentations', nextRow).length == $('.indentations', changedRow)) {

          sourceRow = nextRow;

        }

      }

      else {

        sourceRow = nextRow;

      }

    }

  }

  // Parents, look up the tree until we find a field not in this group.

  // Go up as many parents as indentations in the changed row.

  else if (rowSettings.relationship == 'parent') {

    var previousRow = $(changedRow).prev('tr');

    while (previousRow.length && $('.indentation', previousRow).length >= this.rowObject.indents) {

      previousRow = previousRow.prev('tr');

    }

    // If we found a row.

    if (previousRow.length) {

      sourceRow = previousRow[0];

    }

    // Otherwise we went all the way to the left of the table without finding

    // a parent, meaning this item has been placed at the root level.

    else {

      // Use the first row in the table as source, because it's guaranteed to

      // be at the root level. Find the first item, then compare this row

      // against it as a sibling.

      sourceRow = $(this.table).find('tr.draggable:first').get(0);

      if (sourceRow == this.rowObject.element) {

        sourceRow = $(this.rowObject.group[this.rowObject.group.length - 1]).next('tr.draggable').get(0);

      }

      var useSibling = true;

    }

  }

  // Because we may have moved the row from one category to another,

  // take a look at our sibling and borrow its sources and targets.

  this.copyDragClasses(sourceRow, changedRow, group);

  rowSettings = this.rowSettings(group, changedRow);

  // In the case that we're looking for a parent, but the row is at the top

  // of the tree, copy our sibling's values.

  if (useSibling) {

    rowSettings.relationship = 'sibling';

    rowSettings.source = rowSettings.target;

  }

  var targetClass = '.' + rowSettings.target;

  var targetElement = $(targetClass, changedRow).get(0);

  // Check if a target element exists in this row.

  if (targetElement) {

    var sourceClass = '.' + rowSettings.source;

    var sourceElement = $(sourceClass, sourceRow).get(0);

    switch (rowSettings.action) {

      case 'depth':

        // Get the depth of the target row.

        targetElement.value = $('.indentation', $(sourceElement).closest('tr')).length;

        break;

      case 'match':

        // Update the value.

        targetElement.value = sourceElement.value;

        break;

      case 'order':

        var siblings = this.rowObject.findSiblings(rowSettings);

        if ($(targetElement).is('select')) {

          // Get a list of acceptable values.

          var values = [];

          $('option', targetElement).each(function () {

            values.push(this.value);

          });

          var maxVal = values[values.length - 1];

          // Populate the values in the siblings.

          $(targetClass, siblings).each(function () {

            // If there are more items than possible values, assign the maximum value to the row.

            if (values.length > 0) {

              this.value = values.shift();

            }

            else {

              this.value = maxVal;

            }

          });

        }

        else {

          // Assume a numeric input field.

          var weight = parseInt($(targetClass, siblings[0]).val(), 10) || 0;

          $(targetClass, siblings).each(function () {

            this.value = weight;

            weight++;

          });

        }

        break;

    }

  }

};

/**

 * Copy all special tableDrag classes from one row's form elements to a

 * different one, removing any special classes that the destination row

 * may have had.

 */

Drupal.tableDrag.prototype.copyDragClasses = function (sourceRow, targetRow, group) {

  var sourceElement = $('.' + group, sourceRow);

  var targetElement = $('.' + group, targetRow);

  if (sourceElement.length && targetElement.length) {

    targetElement[0].className = sourceElement[0].className;

  }

};

Drupal.tableDrag.prototype.checkScroll = function (cursorY) {

  var de  = document.documentElement;

  var b  = document.body;

  var windowHeight = this.windowHeight = window.innerHeight || (de.clientHeight && de.clientWidth != 0 ? de.clientHeight : b.offsetHeight);

  var scrollY = this.scrollY = (document.all ? (!de.scrollTop ? b.scrollTop : de.scrollTop) : (window.pageYOffset ? window.pageYOffset : window.scrollY));

  var trigger = this.scrollSettings.trigger;

  var delta = 0;

  // Return a scroll speed relative to the edge of the screen.

  if (cursorY - scrollY > windowHeight - trigger) {

    delta = trigger / (windowHeight + scrollY - cursorY);

    delta = (delta > 0 && delta < trigger) ? delta : trigger;

    return delta * this.scrollSettings.amount;

  }

  else if (cursorY - scrollY < trigger) {

    delta = trigger / (cursorY - scrollY);

    delta = (delta > 0 && delta < trigger) ? delta : trigger;

    return -delta * this.scrollSettings.amount;

  }

};

Drupal.tableDrag.prototype.setScroll = function (scrollAmount) {

  var self = this;

  this.scrollInterval = setInterval(function () {

    // Update the scroll values stored in the object.

    self.checkScroll(self.currentMouseCoords.y);

    var aboveTable = self.scrollY > self.table.topY;

    var belowTable = self.scrollY + self.windowHeight < self.table.bottomY;

    if (scrollAmount > 0 && belowTable || scrollAmount < 0 && aboveTable) {

      window.scrollBy(0, scrollAmount);

    }

  }, this.scrollSettings.interval);

};

Drupal.tableDrag.prototype.restripeTable = function () {

  // :even and :odd are reversed because jQuery counts from 0 and

  // we count from 1, so we're out of sync.

  // Match immediate children of the parent element to allow nesting.

  $('> tbody > tr.draggable:visible, > tr.draggable:visible', this.table)

    .removeClass('odd even')

    .filter(':odd').addClass('even').end()

    .filter(':even').addClass('odd');

};

/**

 * Stub function. Allows a custom handler when a row begins dragging.

 */

Drupal.tableDrag.prototype.onDrag = function () {

  return null;

};

/**

 * Stub function. Allows a custom handler when a row is dropped.

 */

Drupal.tableDrag.prototype.onDrop = function () {

  return null;

};

/**

 * Constructor to make a new object to manipulate a table row.

 *