diff --git a/content/completion.js b/content/completion.js
index 97fb9289..37e55a56 100644
--- a/content/completion.js
+++ b/content/completion.js
@@ -554,7 +554,7 @@ vimperator.Completion = function () // {{{
         // items must be an array of strings
         match: function (items, filter, case_sensitive)
         {
-            if (typeof(filter) != "string" || !items)
+            if (typeof filter != "string" || !items)
                 return false;
 
             var items_str = items.join(" ");
diff --git a/content/util.js b/content/util.js
index 9f8f5e83..c39c91e0 100644
--- a/content/util.js
+++ b/content/util.js
@@ -43,7 +43,7 @@ vimperator.util = {
     // any line breaks are displayed as \n
     colorize: function (arg, process_strings)
     {
-        var type = typeof(arg);
+        var type = typeof arg;
 
         // some objects like window.JSON or getBrowsers()._browsers need the try/catch
         try
diff --git a/content/vimperator.js b/content/vimperator.js
index 4bdce7e5..b6ba570e 100644
--- a/content/vimperator.js
+++ b/content/vimperator.js
@@ -418,7 +418,7 @@ const vimperator = (function () //{{{
             if (!args)
                 args = [];
 
-            if (typeof(blocking) != "boolean")
+            if (typeof blocking != "boolean")
                 blocking = false;
 
             try