Added add_class and remove_class methods.

IPython/html/static/notebook/js/widget.js

@@ -309,6 +309,8 b' define(["components/underscore/underscore-min",'
             initialize: function() {
                 this.visible = true;
                 this.model.on('change',this.update,this);
+                this._add_class_calls = this.model.get('_add_class')[0];
+                this._remove_class_calls = this.model.get('_remove_class')[0];
             },
             
             update: function() {
@@ -322,25 +324,14 b' define(["components/underscore/underscore-min",'
                         }
                     }
                 }
+
                 if (this.model.css != undefined) {
                     for (var selector in this.model.css) {
                         if (this.model.css.hasOwnProperty(selector)) {
                             
-                            // Get the elements via the css selector.  If the selector is
-                            // blank, apply the style to the $el_to_style element.  If
-                            // the $el_to_style element is not defined, use apply the 
-                            // style to the view's element.
-                            var elements = this.$el.find(selector);
-                            if (selector=='') {
-                                if (this.$el_to_style == undefined) {
-                                    elements = this.$el;
-                                } else {
-                                    elements = this.$el_to_style;
-                                }
-                            }
-                            
                             // Apply the css traits to all elements that match the selector.
-                            if (elements.length>0){
+                            var elements = this.get_selector_element(selector);
+                            if (elements.length > 0) {
                                 var css_traits = this.model.css[selector];    
                                 for (var css_key in css_traits) {
                                     if (css_traits.hasOwnProperty(css_key)) {
@@ -351,6 +342,46 b' define(["components/underscore/underscore-min",'
                         }
                     }
                 }
+
+                var add_class = this.model.get('_add_class');
+                if (add_class != undefined){
+                    var add_class_calls = add_class[0];
+                    if (add_class_calls > this._add_class_calls) {
+                        this._add_class_calls = add_class_calls;
+                        var elements = this.get_selector_element(add_class[1]);
+                        if (elements.length > 0) {
+                            elements.addClass(add_class[2]);
+                        }
+                    }    
+                }
+
+                var remove_class = this.model.get('_remove_class');
+                if (remove_class != undefined){
+                    var remove_class_calls = remove_class[0];
+                    if (remove_class_calls > this._remove_class_calls) {
+                        this._remove_class_calls = remove_class_calls;
+                        var elements = this.get_selector_element(remove_class[1]);
+                        if (elements.length > 0) {
+                            elements.removeClass(remove_class[2]);
+                        }
+                    }    
+                }
+            },
+
+            get_selector_element: function(selector) {
+                // Get the elements via the css selector.  If the selector is
+                // blank, apply the style to the $el_to_style element.  If
+                // the $el_to_style element is not defined, use apply the 
+                // style to the view's element.
+                var elements = this.$el.find(selector);
+                if (selector=='') {
+                    if (this.$el_to_style == undefined) {
+                        elements = this.$el;
+                    } else {
+                        elements = this.$el_to_style;
+                    }
+                }
+                return elements;
             },
         });
 

IPython/html/widgets/widget.py

@@ -44,6 +44,9 b' def init_widget_js():'
 #-----------------------------------------------------------------------------
 class Widget(LoggingConfigurable):
 
+    # Shared declarations
+    _keys = []
+    
     # Public declarations
     target_name = Unicode('widget', help="""Name of the backbone model 
         registered in the frontend to create and sync this widget with.""")
@@ -64,11 +67,12 b' class Widget(LoggingConfigurable):'
                 new._children.append(self)
             if old is not None and self in old._children:
                 old._children.remove(self)                
-    
+
     # Private/protected declarations
-    _keys = []
     _property_lock = False
-    _css = Dict()
+    _css = Dict() # Internal CSS property dict
+    _add_class = List() # Used to add a js class to a DOM element (call#, selector, class_name)
+    _remove_class = List() # Used to remove a js class from a DOM element (call#, selector, class_name)
     _displayed = False
     _comm = None
     
@@ -87,6 +91,8 b' class Widget(LoggingConfigurable):'
             via the default_view_name property.
         """
         self._children = []
+        self._add_class = [0]
+        self._remove_class = [0]
         super(Widget, self).__init__(**kwargs)
                 
         # Register after init to allow default values to be specified
@@ -108,7 +114,7 b' class Widget(LoggingConfigurable):'
     
     # Properties      
     def _get_keys(self):
-        keys = ['_css', 'visible']
+        keys = ['visible', '_css', '_add_class', '_remove_class']
         keys.extend(self._keys)
         return keys
     keys = property(_get_keys)
@@ -212,7 +218,39 b' class Widget(LoggingConfigurable):'
         # Only update the property if it has changed.
         if not (key in self._css[selector] and value in self._css[selector][key]):
             self._css[selector][key] = value
-            self.send_state() # Send new state to client.
+            self.send_state('_css') # Send new state to client.
+
+
+    def add_class(self, class_name, selector=""):
+        """Add class[es] to a DOM element
+
+        Parameters
+        ----------
+        class_name: unicode
+            Class name(s) to add to the DOM element(s).  Multiple class names 
+            must be space separated.
+        selector: unicode (optional)
+            JQuery selector to select the DOM element(s) that the class(es) will 
+            be added to.
+        """
+        self._add_class = [self._add_class[0] + 1, selector, class_name]
+        self.send_state(key='_add_class')
+
+
+    def remove_class(self, class_name, selector=""):
+        """Remove class[es] from a DOM element
+
+        Parameters
+        ----------
+        class_name: unicode
+            Class name(s) to remove from  the DOM element(s).  Multiple class 
+            names must be space separated.
+        selector: unicode (optional)
+            JQuery selector to select the DOM element(s) that the class(es) will 
+            be removed from.
+        """
+        self._remove_class = [self._remove_class[0] + 1, selector, class_name]
+        self.send_state(key='_remove_class')
 
 
     # Support methods