Index: misc/tabledrag.js
===================================================================
RCS file: /cvs/drupal/drupal/misc/tabledrag.js,v
retrieving revision 1.38
diff -u -p -r1.38 tabledrag.js
--- tabledrag.js	18 May 2010 06:46:45 -0000	1.38
+++ tabledrag.js	31 May 2010 07:05:48 -0000
@@ -81,10 +81,22 @@
 
   // 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); });
+  $('> tr.draggable, > tbody > tr.draggable', table).each(function () { self.makeDraggable(this); });
 
-  // Hide columns containing affected form elements.
-  this.hideColumns();
+  // Add a link before the table for users to show or hide weight columns.
+  $(table).before($('<a href="#" class="tabledrag-toggle-weight"></a>')
+    .click(function () {
+      self.toggleShowWeight(self);
+      return false;
+    })
+    .wrap('<div class="tabledrag-toggle-weight-wrapper"></div>')
+    .parent()
+  );
+
+  // Hide or show weight and parent columns according to user preference.
+  // This aids screenreader accessibility so users can enter weight values.
+  // Initialize the weight columns for the show/hide toggle.
+  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.
@@ -93,10 +105,13 @@
 };
 
 /**
- * Hide the columns containing form elements according to the settings for
- * this tableDrag instance.
- */
-Drupal.tableDrag.prototype.hideColumns = function () {
+ * Initialize weight/parent columns to be hidden by default.
+ *
+ * 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]) {
@@ -108,13 +123,13 @@
       }
     }
 
-    // Hide the column containing this field.
+    // Mark the column containing this field so it can be hidden.
     if (hidden && cell[0] && cell.css('display') != 'none') {
       // 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;
       var headerIndex = $('> td:not(:hidden)', cell.parent()).index(cell.get(0)) + 1;
-      $('> thead > tr, > tbody > tr, > tr', this.table).each(function(){
+      $('> thead > tr, > tbody > tr, > tr', this.table).each(function (){
         var row = $(this);
         var parentTag = row.parent().get(0).tagName.toLowerCase();
         var index = (parentTag == 'thead') ? headerIndex : columnIndex;
@@ -128,21 +143,104 @@
         if (index > 0) {
           cell = row.children(':nth-child(' + index + ')');
           if (cell[0].colSpan > 1) {
-            // If this cell has a colspan, simply reduce it.
-            cell[0].colSpan = cell[0].colSpan - 1;
+            // If this cell has a colspan, mark it so we can reduce the colspan.
+            $(cell[0]).addClass('tabledrag-reduce-colspan');
           }
           else {
-            // Hide table body cells, but remove table header cells entirely
-            // (Safari doesn't hide properly).
-            parentTag == 'thead' ? cell.remove() : cell.css('display', 'none');
+            // Mark this cell so we can hide it.
+            $(cell[0]).addClass('tabledrag-hide');
           }
         }
       });
     }
   }
+
+  // Now hide cells and reduce colspans unless cookie indicates previous choice.
+  // Set a cookie if it is not already present.
+  if ($.cookie('Drupal.tableDrag.showWeight') === null) {
+    $.cookie('Drupal.tableDrag.showWeight', 0, {
+      path: Drupal.settings.basePath,
+      // The cookie expires in one year.
+      expires: 365
+    }
+    );
+    this.hideColumns();
+  }
+  // Check cookie value and show/hide weight columns accordingly.
+  // The following code is basically identical to toggleShowWeight().
+  else {
+    if ($.cookie('Drupal.tableDrag.showWeight') == 1) {
+      this.showColumns();
+    }
+    else {
+      this.hideColumns();
+    }
+//    this.toggleShowWeight(self);
+  }
 };
 
 /**
+ * Hide the columns containing weight/parent form elements.
+ * Undo showColumns().
+ */
+Drupal.tableDrag.prototype.hideColumns = function () {
+  // Turn off display of weight/parent cells and headers.
+  $('.tabledrag-hide').css('display', 'none');
+  // Show TableDrag handles.
+  $('.tabledrag-handle').css('display', '');
+  // Reduce colspan of any effected multi-span columns.
+  $('.tabledrag-reduce-colspan').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
+    }
+  );
+}
+
+/**
+ * Show the columns containing weight/parent form elements
+ * Undo hideColumns().
+ */
+Drupal.tableDrag.prototype.showColumns = function () {
+  // Turn on display of weight/parent cells and headers.
+  $('.tabledrag-hide').css('display', '');
+  // Hide TableDrag handles.
+  $('.tabledrag-handle').css('display', 'none');
+  // Increase colspan back to columns it was reduced.
+  $('.tabledrag-reduce-colspan').each(function () {
+    this.colSpan = this.colSpan + 1;
+  });
+  // Change link text.
+  $('.tabledrag-toggle-weight').text(Drupal.t('Hide row weights'));
+  // Change cookie.
+  $.cookie('Drupal.tableDrag.showWeight', 1, {
+    path: Drupal.settings.basePath,
+    // The cookie expires in one year.
+    expires: 365
+    }
+  );
+}
+
+/**
+ * Toggle visibility of weight/parent columns. Use a saved cookie to store the
+ * user preference.
+ */
+Drupal.tableDrag.prototype.toggleShowWeight = function (self) {
+  if ($.cookie('Drupal.tableDrag.showWeight') == 1) {
+    this.hideColumns();
+  }
+  else {
+    this.showColumns();
+  }
+}
+
+/**
  * Find the target used within a particular row and group.
  */
 Drupal.tableDrag.prototype.rowSettings = function (group, row) {
@@ -442,7 +540,7 @@
       // fields in the entire dragged group.
       for (var group in self.tableSettings) {
         var rowSettings = self.rowSettings(group, droppedRow);
-        if (rowSettings.relationship == 'group') {
+        if (rowSettings !== undefined && rowSettings.relationship == 'group') {
           for (var n in self.rowObject.children) {
             self.updateField(self.rowObject.children[n], group);
           }
@@ -594,11 +692,11 @@
   var rowSettings = this.rowSettings(group, changedRow);
 
   // Set the row as it's own target.
-  if (rowSettings.relationship == 'self' || rowSettings.relationship == 'group') {
+  if (rowSettings !== undefined && (rowSettings.relationship == 'self' || rowSettings.relationship == 'group')) {
     var sourceRow = changedRow;
   }
   // Siblings are easy, check previous and next rows.
-  else if (rowSettings.relationship == 'sibling') {
+  else if (rowSettings !== undefined && rowSettings.relationship == 'sibling') {
     var previousRow = $(changedRow).prev('tr').get(0);
     var nextRow = $(changedRow).next('tr').get(0);
     var sourceRow = changedRow;
@@ -625,7 +723,7 @@
   }
   // 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') {
+  else if (rowSettings !== undefined && rowSettings.relationship == 'parent') {
     var previousRow = $(changedRow).prev('tr');
     while (previousRow.length && $('.indentation', previousRow).length >= this.rowObject.indents) {
       previousRow = previousRow.prev('tr');
@@ -660,8 +758,10 @@
     rowSettings.source = rowSettings.target;
   }
 
-  var targetClass = '.' + rowSettings.target;
-  var targetElement = $(targetClass, changedRow).get(0);
+  if(rowSettings !== undefined) {
+    var targetClass = '.' + rowSettings.target;
+    var targetElement = $(targetClass, changedRow).get(0);
+  }
 
   // Check if a target element exists in this row.
   if (targetElement) {