diff --git a/chrome-extension/src/background.js b/chrome-extension/src/background.js
deleted file mode 100644
index 80e64ce..0000000
--- a/chrome-extension/src/background.js
+++ /dev/null
@@ -1,31 +0,0 @@
-// Send message to content.js when URL changes
-chrome.tabs.onUpdated.addListener(function
-  (tabId, changeInfo, tab) {
-    if (changeInfo.url) {
-      chrome.tabs.sendMessage(tabId, {
-        message: 'URL has changed',
-        url: changeInfo.url
-      })
-    }
-  });
-
-chrome.runtime.onInstalled.addListener(function(details) {
-  if (details.reason == "install") {
-    if (chrome.runtime.setUninstallURL) {
-      chrome.runtime.setUninstallURL('https://forms.gle/Cgv34WVhgms9MChv7');
-    }
-  }
-});
-
-chrome.runtime.onMessage.addListener(function(message, sender, sendResponse) {
-  console.log(message);
-  if (message.srmStatus === 'ON') {
-    chrome.pageAction.setIcon({tabId: sender.tab.id, path: 'icon128.png'});
-  }
-  if (message.srmStatus === 'OK') {
-    chrome.pageAction.setIcon({tabId: sender.tab.id, path: 'icon128green.png'});
-  }
-  if (message.srmStatus === 'SRM') {
-    chrome.pageAction.setIcon({tabId: sender.tab.id, path: 'icon128red.png'});
-  }
-});
diff --git a/chrome-extension/src/content.js b/chrome-extension/src/content.js
index 1a64cbe..2aed886 100644
--- a/chrome-extension/src/content.js
+++ b/chrome-extension/src/content.js
@@ -13,12 +13,13 @@ const platforms = {
 
   // SRM Checker Chrome Extension microsite
   // TODO Remove this once we support more than one real platform.
-  'lukasvermeer.nl': {
+  'www.lukasvermeer.nl': {
     init() {
       document.querySelectorAll('input').forEach(i => i.addEventListener('input', () => {
-        const a = parseInt(document.getElementById('atraffic').value, 10);
-        const b = parseInt(document.getElementById('btraffic').value, 10);
-        const e = parseFloat(document.getElementById('expectedprop').value, 10) * 100;
+        const numbers = document.querySelectorAll("input");
+        const a = parseInt(numbers[0].value, 10);
+        const b = parseInt(numbers[2].value, 10);
+        const e = parseFloat(numbers[1].value, 10) * 100;
 
         checkSRM([a, b], [100 - e, e]);
       }, false));
diff --git a/chrome-extension/src/manifest.json b/chrome-extension/src/manifest.json
index 2c73947..5f05994 100644
--- a/chrome-extension/src/manifest.json
+++ b/chrome-extension/src/manifest.json
@@ -1,32 +1,50 @@
 {
   "name": "Sample Ratio Mismatch (SRM) Checker",
   "short_name": "SRM Check",
-  "version": "0.0.8",
+  "version": "0.1.0",
   "description": "Automatically performs Sample Ratio Mismatch (SRM) test and flags potential issues on supported experimentation platforms.",
   "permissions": [
-    "tabs"
+    "activeTab",
+    "scripting"
+  ],
+  "host_permissions": [
+        "https://*.lukasvermeer.nl/srm/*",
+        "https://app.optimizely.com/*",
+        "https://app.vwo.com/*",
+        "https://*.sitegainer.com/*",
+        "https://conversion.symplify.com/*",
+        "https://app.convert.com/*",
+        "https://web.omniconvert.com/*",
+        "https://pagesense.zoho.eu/*",
+        "https://pagesense.zoho.com/*"
   ],
   "content_scripts": [
-   {
-     "matches": ["https://lukasvermeer.nl/srm/*",
-                 "https://app.optimizely.com/*",
-                 "https://app.vwo.com/*",
-                 "https://sitegainer.com/*",
-                 "https://conversion.symplify.com/*",
-                 "https://app.convert.com/*",
-                 "https://web.omniconvert.com/*",
-                 "https://pagesense.zoho.eu/*",
-                 "https://pagesense.zoho.com/*"],
-     "js": ["lib/statistics-distributions.js", "srm.js", "content.js"]
-   }
- ],
+    {
+      "matches": [
+        "https://*.lukasvermeer.nl/srm/*",
+        "https://app.optimizely.com/*",
+        "https://app.vwo.com/*",
+        "https://*.sitegainer.com/*",
+        "https://conversion.symplify.com/*",
+        "https://app.convert.com/*",
+        "https://web.omniconvert.com/*",
+        "https://pagesense.zoho.eu/*",
+        "https://pagesense.zoho.com/*"
+      ],
+      "js": [
+        "lib/statistics-distributions.js",
+        "srm.js",
+        "content.js"
+      ]
+    }
+  ],
   "background": {
-    "scripts": [ "background.js" ]
-  },
-  "page_action": {
+    "service_worker": "service_worker.js"
   },
   "icons": {
     "128": "icon128.png"
   },
-  "manifest_version": 2
+  "manifest_version": 3,
+  "action": {},
+  "content_security_policy": {}
 }
diff --git a/chrome-extension/src/service_worker.js b/chrome-extension/src/service_worker.js
new file mode 100644
index 0000000..7bfdfd0
--- /dev/null
+++ b/chrome-extension/src/service_worker.js
@@ -0,0 +1,40 @@
+// Send message to content.js when URL changes
+chrome.tabs.onActivated.addListener(function (tab) {
+  console.log("TAB CHANGED")
+  // TODO only do this on pages where we have permission
+  chrome.scripting.executeScript({
+    target: { tabId: tab.tabId },
+    files: ["content.js"]
+  });
+})
+
+// Fired when a tab is updated.
+chrome.tabs.onUpdated.addListener(async function (tab) {
+  console.log("TAB UPDATED")
+  // TODO only do this on pages where we have permission
+  chrome.scripting.executeScript({
+    target: { tabId: tab },
+    files: ["content.js"]
+  });
+})
+
+chrome.runtime.onInstalled.addListener(function(details) {
+  if (details.reason == "install") {
+    if (chrome.runtime.setUninstallURL) {
+      chrome.runtime.setUninstallURL('https://forms.gle/Cgv34WVhgms9MChv7');
+    }
+  }
+});
+
+chrome.runtime.onMessage.addListener(function(message, sender, sendResponse) {
+  console.log(message);
+  if (message.srmStatus === 'ON') {
+    chrome.action.setIcon({tabId: sender.tab.id, path: 'icon128.png'});
+  }
+  if (message.srmStatus === 'OK') {
+    chrome.action.setIcon({tabId: sender.tab.id, path: 'icon128green.png'});
+  }
+  if (message.srmStatus === 'SRM') {
+    chrome.action.setIcon({tabId: sender.tab.id, path: 'icon128red.png'});
+  }
+});