diff --git a/ext/fg/frame.html b/ext/fg/frame.html
index ecaee323..80e69967 100644
--- a/ext/fg/frame.html
+++ b/ext/fg/frame.html
@@ -32,9 +32,10 @@
 
         <script src="/mixed/lib/jquery.min.js"></script>
         <script src="/mixed/lib/wanakana.min.js"></script>
-        <script src="/fg/js/util.js"></script>
         <script src="/mixed/js/audio.js"></script>
         <script src="/mixed/js/display.js"></script>
+        <script src="/fg/js/dictionary.js"></script>
+        <script src="/fg/js/background.js"></script>
         <script src="/fg/js/display-frame.js"></script>
     </body>
 </html>
diff --git a/ext/fg/js/background.js b/ext/fg/js/background.js
new file mode 100644
index 00000000..52b533be
--- /dev/null
+++ b/ext/fg/js/background.js
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2016  Alex Yatskov <alex@foosoft.net>
+ * Author: Alex Yatskov <alex@foosoft.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+function bgInvoke(action, params={}) {
+    return new Promise((resolve, reject) => {
+        try {
+            chrome.runtime.sendMessage({action, params}, ({result, error}) => {
+                if (error) {
+                    reject(error);
+                } else {
+                    resolve(result);
+                }
+            });
+        } catch (e) {
+            window.orphaned = true;
+            reject(e.message);
+        }
+    });
+}
+
+function bgOptionsGet() {
+    return bgInvoke('optionsGet');
+}
+
+function bgTermsFind(text) {
+    return bgInvoke('termsFind', {text});
+}
+
+function bgKanjiFind(text) {
+    return bgInvoke('kanjiFind', {text});
+}
+
+function bgTemplateRender(template, data) {
+    return bgInvoke('templateRender', {data, template});
+}
+
+function bgDefinitionsAddable(definitions, modes) {
+    return bgInvoke('definitionsAddable', {definitions, modes}).catch(() => null);
+}
+
+function bgDefinitionAdd(definition, mode) {
+    return bgInvoke('definitionAdd', {definition, mode});
+}
+
+function bgNoteView(noteId) {
+    return bgInvoke('noteView', {noteId});
+}
diff --git a/ext/fg/js/util.js b/ext/fg/js/document.js
similarity index 82%
rename from ext/fg/js/util.js
rename to ext/fg/js/document.js
index 2acd81c4..582b6770 100644
--- a/ext/fg/js/util.js
+++ b/ext/fg/js/document.js
@@ -17,59 +17,6 @@
  */
 
 
-/*
- * Background
- */
-
-function bgInvoke(action, params) {
-    return new Promise((resolve, reject) => {
-        try {
-            chrome.runtime.sendMessage({action, params}, ({result, error}) => {
-                if (error) {
-                    reject(error);
-                } else {
-                    resolve(result);
-                }
-            });
-        } catch (e) {
-            window.orphaned = true;
-            reject(e.message);
-        }
-    });
-}
-
-function bgOptionsGet() {
-    return bgInvoke('optionsGet', {});
-}
-
-function bgTermsFind(text) {
-    return bgInvoke('termsFind', {text});
-}
-
-function bgKanjiFind(text) {
-    return bgInvoke('kanjiFind', {text});
-}
-
-function bgTemplateRender(template, data) {
-    return bgInvoke('templateRender', {data, template});
-}
-
-function bgDefinitionsAddable(definitions, modes) {
-    return bgInvoke('definitionsAddable', {definitions, modes}).catch(() => null);
-}
-
-function bgDefinitionAdd(definition, mode) {
-    return bgInvoke('definitionAdd', {definition, mode});
-}
-
-function bgNoteView(noteId) {
-    return bgInvoke('noteView', {noteId});
-}
-
-/*
- * Document
- */
-
 function docOffsetCalc(element) {
     const scrollTop = window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop;
     const scrollLeft = window.pageXOffset || document.documentElement.scrollLeft || document.body.scrollLeft;
diff --git a/ext/manifest.json b/ext/manifest.json
index be9f3208..7a277fb2 100644
--- a/ext/manifest.json
+++ b/ext/manifest.json
@@ -15,9 +15,10 @@
     "content_scripts": [{
         "matches": ["http://*/*", "https://*/*", "file://*/*"],
         "js": [
-            "fg/js/util.js",
+            "fg/js/document.js",
             "fg/js/source-range.js",
             "fg/js/source-element.js",
+            "fg/js/background.js",
             "fg/js/popup.js",
             "fg/js/driver.js"
         ],