--- a/mobile/android/chrome/content/browser.js
+++ b/mobile/android/chrome/content/browser.js
@@ -7096,17 +7096,17 @@ HTMLContextMenuItem.prototype = Object.c
   callback: {
     value: function(target) {
       let elt = this.menuElementRef.get();
       if (!elt) {
         return;
       }
 
       // If this is a menu item, show a new context menu with the submenu in it
-      if (elt instanceof Ci.nsIDOMHTMLMenuElement) {
+      if (elt instanceof HTMLMenuElement) {
         try {
           NativeWindow.contextmenus.menus = {};
 
           let elt = this.menuElementRef.get();
           let target = this.targetElementRef.get();
           if (!elt) {
             return;
           }
@@ -7139,14 +7139,14 @@ HTMLContextMenuItem.prototype = Object.c
         return null;
       }
 
       return {
         id: this.id,
         icon: elt.icon,
         label: elt.label,
         disabled: elt.disabled,
-        menu: elt instanceof Ci.nsIDOMHTMLMenuElement
+        menu: elt instanceof HTMLMenuElement
       };
     }
   },
 });