diff --git a/chrome/content/vimperator/commands.js b/chrome/content/vimperator/commands.js
index 45f8c516..679a95ff 100644
--- a/chrome/content/vimperator/commands.js
+++ b/chrome/content/vimperator/commands.js
@@ -1506,7 +1506,7 @@ function set(args, special)
             return;
         }
 
-        var no = true; if (matches[1] == undefined) no = false;
+        var no = true; if (matches[1] === undefined) no = false;
         var opt = matches[2];
         var option = get_option(opt);
         if (!option)
@@ -1516,10 +1516,10 @@ function set(args, special)
         }
 
         var get = false; if (matches[3] == "?" ||
-            (option[TYPE] != 'boolean' && matches[4] == undefined)) get = true;
+            (option[TYPE] != 'boolean' && matches[4] === undefined)) get = true;
         var reset = false; if (matches[3] == "&") reset = true;
         var oper = matches[5];
-        var val = matches[6]; if (val == undefined) val = "";
+        var val = matches[6]; if (val === undefined) val = "";
 
         // reset a variable to its default value.
         if (reset)
diff --git a/chrome/content/vimperator/vimperator.js b/chrome/content/vimperator/vimperator.js
index d2d2e47b..84feb78c 100644
--- a/chrome/content/vimperator/vimperator.js
+++ b/chrome/content/vimperator/vimperator.js
@@ -249,7 +249,7 @@ function Vimperator() //{{{1
         if (typeof(extended) === "number")
             extended_mode = extended;
 
-        if (typeof(silent) == "undefined" || !silent)
+        if (!silent)
             showMode();
     }
     // returns true if "whichmode" is found in either the main or
@@ -739,7 +739,7 @@ function Tabs() //{{{1
         var length   = getBrowser().mTabs.length;
         var last     = length - 1;
 
-        if (typeof(spec) === "undefined" || spec === "")
+        if (spec === undefined || spec === "")
             return position;
 
         if (typeof(spec) === "number")