diff --git a/.jshintrc b/.jshintrc
index 5ff1e697d..79ed65fc1 100644
--- a/.jshintrc
+++ b/.jshintrc
@@ -9,6 +9,7 @@
     "node": true,
     "quotmark": "double",
     "smarttabs": true,
+    "strict": true,
     "trailing": true,
     "undef": true,
     "unused": true
diff --git a/src/.jshintrc b/src/.jshintrc
index d74bf14fd..bc4ae7750 100644
--- a/src/.jshintrc
+++ b/src/.jshintrc
@@ -6,8 +6,10 @@
     "evil": true,
     "expr": true,
     "maxerr": 100,
+    "newcap": false,
     "quotmark": "double",
     "smarttabs": true,
+    "strict": true,
     "sub": true,
     "trailing": true,
     "undef": true,
diff --git a/src/effects.js b/src/effects.js
index dcc6c00b7..7627e3a23 100644
--- a/src/effects.js
+++ b/src/effects.js
@@ -233,6 +233,7 @@ jQuery.Animation = jQuery.extend( Animation, {
 });
 
 function defaultPrefilter( elem, props, opts ) {
+	/*jshint validthis:true */
 	var index, prop, value, length, dataShow, tween, hooks, oldfire,
 		anim = this,
 		style = elem.style,
diff --git a/src/intro.js b/src/intro.js
index c041bb4ba..0b98012ec 100644
--- a/src/intro.js
+++ b/src/intro.js
@@ -12,3 +12,4 @@
  * Date: @DATE
  */
 (function( window, undefined ) {
+"use strict";