diff --git a/background.js b/background.js
index 6c1628d..629adbb 100644
--- a/background.js
+++ b/background.js
@@ -144,16 +144,18 @@ chrome.tabs.query({ active: true, currentWindow: true }, function(tabs) {
   chrome.tabs.sendMessage(tabs[0].id, { action: "getBannedSlogans" }, function(
     response
   ) {
-    let resultContent = "";
-
-    if (response.length == 0) {
-      resultContent = fullDiv("Hooray, no banned words!");
-    } else {
-      response.forEach((slogan, i) => {
-        resultContent += span(span(i + 1) + span(slogan));
-      });
+    if (response) {
+      let resultContent = "";
+
+      if (response.length == 0) {
+        resultContent = fullDiv("Hooray, no banned words!");
+      } else {
+        response.forEach((slogan, i) => {
+          resultContent += span(span(i + 1) + span(slogan));
+        });
+      }
+
+      bannedSlogansList.innerHTML = resultContent;
     }
-
-    bannedSlogansList.innerHTML = resultContent;
   });
 });
diff --git a/content.js b/content.js
index 156ef9a..17ffc90 100644
--- a/content.js
+++ b/content.js
@@ -77,15 +77,16 @@ function startScan() {
         let doc = domParser.parseFromString(text["*"], "text/html");
         parseWikiNodes(doc);
         checkNodeRecursively(body);
-        const observer = new MutationObserver(callback);
-        observer.observe(body, {
-          childList: true,
-          subtree: true
-        });
       });
   } else {
     checkNodeRecursively(body);
   }
+  const observer = new MutationObserver(callback);
+  observer.observe(body, {
+    childList: true,
+    subtree: true
+  });
+
   function checkNode(startNode) {
     if (startNode.nodeType == Node.TEXT_NODE) {
       const value = startNode.nodeValue.toLowerCase();