diff --git a/content/content.js b/content/content.js
index d70d463..5335a00 100644
--- a/content/content.js
+++ b/content/content.js
@@ -1,4 +1,3 @@
-var videoDetected = false;
 var videoChecker;
 
 function checkForVideos() {
@@ -6,9 +5,9 @@ function checkForVideos() {
   if (videos.length > 0) {
     chrome.storage.local.get("state", function(value) {
       const enabled = (value["state"] !== "disabled");
-      if (!videoDetected) {
-        // A video was detected, previously none were.
-        videoDetected = true;
+      // Check whether video previously detected (i.e. already listening to
+      // storage changes).
+      if (!chrome.storage.onChanged.hasListener(handleStorageChanges)) {
         // Listen to changes to the storage made by the popup.
         chrome.storage.onChanged.addListener(handleStorageChanges);
         if (enabled) {
@@ -20,9 +19,7 @@ function checkForVideos() {
       }
       updateUnprocessedVideos(videos, enabled);
     });
-  } else if (videoDetected) {
-    // A video was previously detected, but there aren't any now.
-    videoDetected = false;
+  } else if (chrome.storage.onChanged.hasListener(handleStorageChanges)) {
     // No more video: do not react to subsequent storage changes.
     chrome.storage.onChanged.removeListener(handleStorageChanges);
     // Notify background so that tab icon is changed to pause.
diff --git a/tests/spec/ContentSpec.js b/tests/spec/ContentSpec.js
index b16ad66..4e610cb 100644
--- a/tests/spec/ContentSpec.js
+++ b/tests/spec/ContentSpec.js
@@ -32,68 +32,63 @@ describe("Content script", function() {
     });
 
     it("should do nothing if no videos are detected and none previously were", function() {
-      videoDetected = false;
-
       checkForVideos();
 
       expect(chrome.storage.local.get.notCalled).toBeTruthy();
-      expect(videoDetected).toBeFalsy();
+      expect(chrome.storage.onChanged.addListener.notCalled).toBeTruthy();
       expect(chrome.storage.onChanged.removeListener.notCalled).toBeTruthy();
       expect(chrome.runtime.sendMessage.notCalled).toBeTruthy();
     });
 
     it("should remove listener and notify background if all previsouly detected videos are gone", function() {
-      videoDetected = true;
+      chrome.storage.onChanged.addListener(handleStorageChanges);
 
       checkForVideos();
 
       expect(chrome.storage.local.get.notCalled).toBeTruthy();
       expect(chrome.storage.onChanged.removeListener.calledOnce).toBeTruthy();
-      expect(videoDetected).toBeFalsy();
       expect(chrome.runtime.sendMessage.withArgs({
         active : false
       }).calledOnce).toBeTruthy();
     });
 
-    it("should update unprocessed videos if some videos were previsouly detected", function() {
+    it("should add listener and update unprocessed videos if videos detected for the first time, but not notify background if extension disabled", function() {
       document.body.appendChild(video);
-      videoDetected = true;
       chrome.storage.local.get.withArgs("state").yields({
-        state : "enabled"
+        state : "disabled"
       });
       spyOn(window, "updateUnprocessedVideos");
 
       checkForVideos();
 
       expect(chrome.storage.local.get.calledOnce).toBeTruthy();
-      expect(videoDetected).toBeTruthy();
-      expect(chrome.storage.onChanged.addListener.notCalled).toBeTruthy();
+      expect(chrome.storage.onChanged.addListener.calledOnce).toBeTruthy();
       expect(chrome.runtime.sendMessage.notCalled).toBeTruthy();
       expect(window.updateUnprocessedVideos.calls.mostRecent().args[0][0]).toEqual(video);
-      expect(window.updateUnprocessedVideos.calls.mostRecent().args[1]).toBeTruthy();
+      expect(window.updateUnprocessedVideos.calls.mostRecent().args[1]).toBeFalsy();
     });
 
-    it("should add listener and update unprocessed videos if videos detected for the first time, but not notify background if extension disabled", function() {
+    it("should add listener, update unprocessed videos and notify background if videos detected for the first time and extension enabled", function() {
       document.body.appendChild(video);
-      videoDetected = false;
       chrome.storage.local.get.withArgs("state").yields({
-        state : "disabled"
+        state : "enabled"
       });
       spyOn(window, "updateUnprocessedVideos");
 
       checkForVideos();
 
       expect(chrome.storage.local.get.calledOnce).toBeTruthy();
-      expect(videoDetected).toBeTruthy();
       expect(chrome.storage.onChanged.addListener.calledOnce).toBeTruthy();
-      expect(chrome.runtime.sendMessage.notCalled).toBeTruthy();
+      expect(chrome.runtime.sendMessage.withArgs({
+        active : true
+      }).calledOnce).toBeTruthy();
       expect(window.updateUnprocessedVideos.calls.mostRecent().args[0][0]).toEqual(video);
-      expect(window.updateUnprocessedVideos.calls.mostRecent().args[1]).toBeFalsy();
+      expect(window.updateUnprocessedVideos.calls.mostRecent().args[1]).toBeTruthy();
     });
-
-    it("should add listener, update unprocessed videos and notify background if videos detected for the first time and extension enabled", function() {
+    
+    it("should update unprocessed videos but not notify background if some videos were previsouly detected", function() {
       document.body.appendChild(video);
-      videoDetected = false;
+      chrome.storage.onChanged.addListener(handleStorageChanges);
       chrome.storage.local.get.withArgs("state").yields({
         state : "enabled"
       });
@@ -102,14 +97,11 @@ describe("Content script", function() {
       checkForVideos();
 
       expect(chrome.storage.local.get.calledOnce).toBeTruthy();
-      expect(videoDetected).toBeTruthy();
-      expect(chrome.storage.onChanged.addListener.calledOnce).toBeTruthy();
-      expect(chrome.runtime.sendMessage.withArgs({
-        active : true
-      }).calledOnce).toBeTruthy();
+      expect(chrome.runtime.sendMessage.notCalled).toBeTruthy();
       expect(window.updateUnprocessedVideos.calls.mostRecent().args[0][0]).toEqual(video);
       expect(window.updateUnprocessedVideos.calls.mostRecent().args[1]).toBeTruthy();
     });
+
   });
 
   describe("Update unprocessed videos", function() {