make baseProjectUrl a method in Menubar

IPython/frontend/html/notebook/static/js/menubar.js

@@ -20,6 +20,10 var IPython = (function (IPython) {
         }
     };
 
+    MenuBar.prototype.baseProjectUrl = function(){
+        return $('body').data('baseProjectUrl');
+    }
+
 
     MenuBar.prototype.style = function () {
         this.element.addClass('border-box-sizing');
@@ -37,17 +41,17 var IPython = (function (IPython) {
     MenuBar.prototype.bind_events = function () {
         //  File
         this.element.find('#new_notebook').click(function () {
-            window.open($('body').data('baseProjectUrl')+'new');
+            window.open(this.baseProjectUrl()+'new');
         });
         this.element.find('#open_notebook').click(function () {
-            window.open($('body').data('baseProjectUrl'));
+            window.open(this.baseProjectUrl());
         });
         this.element.find('#rename_notebook').click(function () {
             IPython.save_widget.rename_notebook();
         });
         this.element.find('#copy_notebook').click(function () {
             var notebook_id = IPython.notebook.get_notebook_id();
-            var url = $('body').data('baseProjectUrl') + notebook_id + '/copy';
+            var url = this.baseProjectUrl() + notebook_id + '/copy';
             window.open(url,'_blank');
             return false;
         });
@@ -56,13 +60,13 var IPython = (function (IPython) {
         });
         this.element.find('#download_ipynb').click(function () {
             var notebook_id = IPython.notebook.get_notebook_id();
-            var url = $('body').data('baseProjectUrl') + 'notebooks/' +
+            var url = this.baseProjectUrl() + 'notebooks/' +
                       notebook_id + '?format=json';
             window.location.assign(url);
         });
         this.element.find('#download_py').click(function () {
             var notebook_id = IPython.notebook.get_notebook_id();
-            var url = $('body').data('baseProjectUrl') + 'notebooks/' +
+            var url = this.baseProjectUrl() + 'notebooks/' +
                       notebook_id + '?format=py';
             window.location.assign(url);
         });