diff --git a/lib/matplotlib/backends/backend_webagg_core.py b/lib/matplotlib/backends/backend_webagg_core.py
index c656c9756daa..42fa6ebaa87e 100644
--- a/lib/matplotlib/backends/backend_webagg_core.py
+++ b/lib/matplotlib/backends/backend_webagg_core.py
@@ -319,20 +319,15 @@ class NavigationToolbar2WebAgg(backend_bases.NavigationToolbar2):
         None: None
     }
 
-    def _init_toolbar(self):
-        # Use the standard toolbar items + download button
-        toolitems = (
-            backend_bases.NavigationToolbar2.toolitems +
-            (('Download', 'Download plot', 'download', 'download'),)
-        )
-
-        NavigationToolbar2WebAgg.toolitems = \
-            tuple(
-                (text, tooltip_text, self._jquery_icon_classes[image_file],
-                 name_of_method)
-                for text, tooltip_text, image_file, name_of_method
-                in toolitems if image_file in self._jquery_icon_classes)
 
+    # Use the standard toolbar items + download button
+    toolitems = [(text, tooltip_text, _jquery_icon_classes[image_file], name_of_method)
+                 for text, tooltip_text, image_file, name_of_method
+                 in (backend_bases.NavigationToolbar2.toolitems +
+                     (('Download', 'Download plot', 'download', 'download'),))
+        if image_file in _jquery_icon_classes]
+
+    def _init_toolbar(self):
         self.message = ''
         self.cursor = 0
 
diff --git a/lib/matplotlib/backends/web_backend/mpl.js b/lib/matplotlib/backends/web_backend/mpl.js
index 89fe97c8b5f7..471ba1aa6866 100644
--- a/lib/matplotlib/backends/web_backend/mpl.js
+++ b/lib/matplotlib/backends/web_backend/mpl.js
@@ -1,5 +1,5 @@
-/* Put everything inside the mpl namespace */
-var mpl = {};
+/* Put everything inside the global mpl namespace */
+window.mpl = {};
 
 
 mpl.get_websocket_type = function() {
@@ -56,21 +56,15 @@ mpl.figure = function(figure_id, websocket, ondownload, parent_element) {
 
     this.waiting = false;
 
-    onopen_creator = function(fig) {
-        return function () {
+    this.ws.onopen =  function () {
             fig.send_message("supports_binary", {value: fig.supports_binary});
             fig.send_message("refresh", {});
         }
-    };
-    this.ws.onopen = onopen_creator(fig);
 
-    onload_creator = function(fig) {
-        return function() {
+    this.imageObj.onload = function() {
             fig.context.drawImage(fig.imageObj, 0, 0);
             fig.waiting = false;
         };
-    };
-    this.imageObj.onload = onload_creator(fig);
 
     this.imageObj.onunload = function() {
         this.ws.close();