diff --git a/content/install-hook-openusercss.js b/content/install-hook-openusercss.js
index 2f77584d..4a392088 100644
--- a/content/install-hook-openusercss.js
+++ b/content/install-hook-openusercss.js
@@ -1,69 +1,81 @@
 'use strict';
 
-(() => {
-  const manifest = chrome.runtime.getManifest();
-  const allowedOrigins = [
-    'https://openusercss.org',
-    'https://openusercss.com'
-  ];
+const manifest = chrome.runtime.getManifest();
+const allowedOrigins = [
+  'https://openusercss.org',
+  'https://openusercss.com'
+];
 
+const askHandshake = () => {
   // Tell the page that we exist and that it should send the handshake
   allowedOrigins.forEach(origin => {
     window.postMessage({
       'type': 'ouc-begin-handshake'
     }, origin);
   });
+};
 
-  // Wait for the handshake
+const doHandshake = () => {
+  // This is a representation of features that Stylus is capable of
+  const implementedFeatures = [
+    'install-usercss',
+    'install-usercss-event',
+    'configure-after-install',
+    'builtin-editor',
+    'create-usercss',
+    'edit-usercss',
+    'import-moz-export',
+    'export-moz-export',
+    'update-manual',
+    'update-auto',
+    'export-json-backups',
+    'import-json-backups',
+    'manage-local'
+  ];
+  const reportedFeatures = [];
+
+  // The handshake question includes a list of required and optional features
+  // we match them with features we have implemented, and build a union array.
+  event.data.featuresList.required.forEach(feature => {
+    if (implementedFeatures.includes(feature)) {
+      reportedFeatures.push(feature);
+    }
+  });
+
+  event.data.featuresList.optional.forEach(feature => {
+    if (implementedFeatures.includes(feature)) {
+      reportedFeatures.push(feature);
+    }
+  });
+
+  // We send the handshake response, which includes the key we got, plus some
+  // additional metadata
+  allowedOrigins.forEach(origin => {
+    window.postMessage({
+      'type':      'ouc-handshake-response',
+      'key':       event.data.key,
+      'extension': {
+        'name':         manifest.name,
+        'capabilities': reportedFeatures
+      }
+    }, origin);
+  });
+};
+
+const attachHandshakeListeners = () => {
+  // Wait for the handshake request, then start it
   window.addEventListener('message', event => {
     if (
       event.data
       && event.data.type === 'ouc-handshake-question'
       && allowedOrigins.includes(event.origin)
     ) {
-      // This is a representation of features that Stylus is capable of
-      const implementedFeatures = [
-        'install-usercss',
-        'configure-after-install',
-        'builtin-editor',
-        'create-usercss',
-        'edit-usercss',
-        'import-moz-export',
-        'export-moz-export',
-        'update-manual',
-        'update-auto',
-        'export-json-backups',
-        'import-json-backups',
-        'manage-local'
-      ];
-      const reportedFeatures = [];
-
-      // The handshake question includes a list of required and optional features
-      // we match them with features we have implemented, and build a union array.
-      event.data.featuresList.required.forEach(feature => {
-        if (implementedFeatures.includes(feature)) {
-          reportedFeatures.push(feature);
-        }
-      });
-
-      event.data.featuresList.optional.forEach(feature => {
-        if (implementedFeatures.includes(feature)) {
-          reportedFeatures.push(feature);
-        }
-      });
-
-      // We send the handshake response, which includes the key we got, plus some
-      // additional metadata
-      allowedOrigins.forEach(origin => {
-        window.postMessage({
-          'type':      'ouc-handshake-response',
-          'key':       event.data.key,
-          'extension': {
-            'name':         manifest.name,
-            'capabilities': reportedFeatures
-          }
-        }, origin);
-      });
+      doHandshake();
     }
   });
+};
+
+(() => {
+  attachHandshakeListeners();
+  askHandshake();
 })();