diff --git a/ext/bg/js/yomichan.js b/ext/bg/js/yomichan.js
index 0187f76f..1714e778 100644
--- a/ext/bg/js/yomichan.js
+++ b/ext/bg/js/yomichan.js
@@ -156,6 +156,10 @@ class Yomichan {
         this.ankiInvoke('modelNames', {}, null, callback);
     }
 
+    api_getModelFieldNames({callback}) {
+        this.ankiInvoke('modelFieldNames', {}, null, callback);
+    }
+
     api_getOptions({callback}) {
         callback(this.options);
     }
diff --git a/ext/bg/options.html b/ext/bg/options.html
index cd0710aa..ae7e4257 100644
--- a/ext/bg/options.html
+++ b/ext/bg/options.html
@@ -100,7 +100,7 @@
                                         <th>Value</th>
                                     </tr>
                                 </thead>
-                                <tbody id="ankiVocabFields">
+                                <tbody class="ankiFields">
                                 </tbody>
                             </table>
                         </div>
@@ -126,7 +126,7 @@
                                         <th>Value</th>
                                     </tr>
                                 </thead>
-                                <tbody id="ankiKanjiFields">
+                                <tbody class="ankiFields">
                                 </tbody>
                             </table>
                         </div>
diff --git a/ext/fg/js/api.js b/ext/fg/js/api.js
index 462eafd1..ecd8dd36 100644
--- a/ext/fg/js/api.js
+++ b/ext/fg/js/api.js
@@ -17,10 +17,6 @@
  */
 
 
-//
-// Background APIs
-//
-
 function bgSendMessage(action, params, callback) {
     chrome.runtime.sendMessage({action, params}, callback);
 }
diff --git a/ext/fg/js/client.js b/ext/fg/js/client.js
index bb25c4e4..932cd10f 100644
--- a/ext/fg/js/client.js
+++ b/ext/fg/js/client.js
@@ -104,6 +104,7 @@ class Client {
             } else {
                 const sequence = ++this.sequence;
                 range.setLength(length);
+
                 bgRenderText(
                     {defs: definitions, root: this.fgRoot, options: this.options, sequence: sequence},
                     'term-list.html',
diff --git a/ext/fg/js/frame.js b/ext/fg/js/frame.js
index 66d3a054..a61bb9ee 100644
--- a/ext/fg/js/frame.js
+++ b/ext/fg/js/frame.js
@@ -42,26 +42,25 @@ function onDomContentLoaded() {
 }
 
 function onMessage(e) {
-    const {action, params} = e.data, handlers = {
-        setActionState: ({index, state, sequence}) => {
-            for (const mode in state) {
-                const matches = document.querySelectorAll(`.action-link[data-sequence="${sequence}"][data-index="${index}"][data-mode="${mode}"]`);
-                if (matches.length === 0) {
-                    return;
-                }
+    const {action, params} = e.data, method = window['api_' + action];
+    if (typeof(method) === 'function') {
+        method(params);
+    }
+}
 
-                const classes = matches[0].classList;
-                if (state[mode]) {
-                    classes.remove('disabled');
-                } else {
-                    classes.add('disabled');
-                }
-            }
+function api_setActionState({index, state, sequence}) {
+    for (const mode in state) {
+        const matches = document.querySelectorAll(`.action-link[data-sequence="${sequence}"][data-index="${index}"][data-mode="${mode}"]`);
+        if (matches.length === 0) {
+            return;
         }
-    };
 
-    if (handlers.hasOwnProperty(action)) {
-        handlers[action](params);
+        const classes = matches[0].classList;
+        if (state[mode]) {
+            classes.remove('disabled');
+        } else {
+            classes.add('disabled');
+        }
     }
 }