Added support for disabled flag to button widget.

IPython/html/static/notebook/js/widgets/button.js

@@ -1,59 +1,65
 //----------------------------------------------------------------------------
 //  Copyright (C) 2013 The IPython Development Team
 //
 //  Distributed under the terms of the BSD License.  The full license is in
 //  the file COPYING, distributed as part of this software.
 //----------------------------------------------------------------------------
 
 //============================================================================
 // ButtonWidget
 //============================================================================
 
 /**
  * @module IPython
  * @namespace IPython
  **/
 
 define(["notebook/js/widget"], function(widget_manager){
     
     var ButtonWidgetModel = IPython.WidgetModel.extend({});
     widget_manager.register_widget_model('ButtonWidgetModel', ButtonWidgetModel);
 
     var ButtonView = IPython.WidgetView.extend({
       
         // Called when view is rendered.
         render : function(){
             var that = this;
             this.setElement($("<button />")
                 .addClass('btn'));
 
             this.update(); // Set defaults.
         },
         
         // Handles: Backend -> Frontend Sync
         //          Frontent -> Frontend Sync
         update : function(){
             var description = this.model.get('description');
             description = description.replace(/ /g, '&nbsp;', 'm');
             description = description.replace(/\n/g, '<br>\n', 'm');
             if (description.length == 0) {
                 this.$el.html('&nbsp;'); // Preserve button height
             } else {
                 this.$el.html(description);
             }
             
+            if (this.model.get('disabled')) {
+                this.$el.attr('disabled','disabled');
+            } else {
+                this.$el.removeAttr('disabled');
+            }
+
             return IPython.WidgetView.prototype.update.call(this);
         },
 
         events: {
             'click': '_handle_click',
         },
         
         _handle_click: function(){
             this.send({event: 'click'});
         },
     });
 
     widget_manager.register_widget_view('ButtonView', ButtonView);
 
 });