diff --git a/manifest-chrome.partial.json b/manifest-chrome.partial.json
index 6296876..5232b1a 100644
--- a/manifest-chrome.partial.json
+++ b/manifest-chrome.partial.json
@@ -5,5 +5,12 @@
     "background": {
         "service_worker": "dist/backgroundScript.js",
         "type": "module"
-    }
+    },
+    "content_scripts": [
+        {
+            "matches": ["*://codeforces.com/*", "*://*.codeforces.com/*"],
+            "js": ["dist/contentScript.js"],
+            "run_at": "document_start"
+        }
+    ]
 }
diff --git a/manifest-firefox.partial.json b/manifest-firefox.partial.json
index 4ad3bee..311ff3b 100644
--- a/manifest-firefox.partial.json
+++ b/manifest-firefox.partial.json
@@ -14,5 +14,12 @@
             "id": "{5dd8fd6e-0733-41a7-abc4-e19fba703de9}",
             "strict_min_version": "49.0"
         }
-    }
+    },
+    "content_scripts": [
+        {
+            "matches": ["*://codeforces.com/*", "*://*.codeforces.com/*"],
+            "js": ["dist/contentScript.js"],
+            "run_at": "document_start"
+        }
+    ]
 }
diff --git a/manifest.json b/manifest.json
new file mode 100644
index 0000000..cbfc18d
--- /dev/null
+++ b/manifest.json
@@ -0,0 +1,24 @@
+{
+    "name": "CPH Submit",
+    "author": "agrawal-d@outlook.com",
+    "homepage_url": "https://github.com/agrawal-d/cph-submit",
+    "version": "1.4.0",
+    "description": "Codeforces Submit add-on for Competitive Programming Helper.",
+    "icons": {
+        "48": "icon-48.png"
+    },
+    "manifest_version": 3,
+    "permissions": ["scripting", "webNavigation"],
+    "host_permissions": ["http://localhost/*", "https://codeforces.com/*"],
+    "background": {
+        "service_worker": "dist/backgroundScript.js",
+        "type": "module"
+    },
+    "content_scripts": [
+        {
+            "matches": ["*://codeforces.com/*", "*://*.codeforces.com/*"],
+            "js": ["dist/contentScript.js"],
+            "run_at": "document_start"
+        }
+    ]
+}
diff --git a/src/backgroundScript.ts b/src/backgroundScript.ts
index 7171167..afe16e9 100644
--- a/src/backgroundScript.ts
+++ b/src/backgroundScript.ts
@@ -4,6 +4,27 @@ import { CphSubmitResponse, CphEmptyResponse } from './types';
 import { handleSubmit } from './handleSubmit';
 import log from './log';
 
+declare const browser: any;
+
+if (typeof browser !== 'undefined') {
+    self.chrome = browser;
+}
+
+// Track connected ports to keep service worker alive
+const connectedPorts: Set<chrome.runtime.Port> = new Set();
+
+chrome.runtime.onConnect.addListener((port) => {
+    if (port.name === 'cph-keep-alive') {
+        connectedPorts.add(port);
+        log('Keep-alive port connected, total ports:', connectedPorts.size);
+
+        port.onDisconnect.addListener(() => {
+            connectedPorts.delete(port);
+            log('Keep-alive port disconnected, total ports:', connectedPorts.size);
+        });
+    }
+});
+
 const mainLoop = async () => {
     let cphResponse;
     try {
diff --git a/src/contentScript.ts b/src/contentScript.ts
new file mode 100644
index 0000000..373a530
--- /dev/null
+++ b/src/contentScript.ts
@@ -0,0 +1,33 @@
+// Content script for Codeforces pages - keeps service worker alive
+import log from './log';
+
+declare const browser: any;
+declare const self: any;
+
+if (typeof browser !== 'undefined') {
+    self.chrome = browser;
+}
+
+log('CPH-Submit content script loaded on Codeforces');
+
+// Establish keep-alive connection
+let port: any = null;
+
+const connectKeepAlive = () => {
+    try {
+        port = chrome.runtime.connect({ name: 'cph-keep-alive' });
+        log('Keep-alive port connected');
+
+        port.onDisconnect.addListener(() => {
+            log('Keep-alive port disconnected');
+            port = null;
+            // Reconnect after short delay
+            setTimeout(connectKeepAlive, 1000);
+        });
+    } catch (err) {
+        log('Failed to connect keep-alive port', err);
+        setTimeout(connectKeepAlive, 1000);
+    }
+};
+
+connectKeepAlive();
diff --git a/src/handleSubmit.ts b/src/handleSubmit.ts
index 3b0c677..c4238e5 100644
--- a/src/handleSubmit.ts
+++ b/src/handleSubmit.ts
@@ -60,14 +60,26 @@ export const handleSubmit = async (
             files: ['/dist/injectedScript.js'],
         });
     }
-    chrome.tabs.sendMessage(tabId, {
-        type: 'cph-submit',
-        problemName,
-        languageId,
-        sourceCode,
-        url: problemUrl,
-    });
-    log('Sending message to tab with script');
+    // Wait for tab to fully load before sending message
+    const sendMessageWhenReady = () => {
+        chrome.tabs.get(tabId, (tab) => {
+            if (tab.status === 'complete') {
+                chrome.tabs.sendMessage(tabId, {
+                    type: 'cph-submit',
+                    problemName,
+                    languageId,
+                    sourceCode,
+                    url: problemUrl,
+                });
+                log('Message sent to fully loaded tab');
+            } else {
+                // Retry after short delay
+                log('Tab not ready, retrying...');
+                setTimeout(sendMessageWhenReady, 100);
+            }
+        });
+    };
+    sendMessageWhenReady();
 
     const filter = {
         url: [{ urlContains: 'codeforces.com/problemset/status' }],
diff --git a/webpack.config.js b/webpack.config.js
index c430d13..f063491 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -4,6 +4,7 @@ module.exports = {
     entry: {
         backgroundScript: './src/backgroundScript.ts',
         injectedScript: './src/injectedScript.ts',
+        contentScript: './src/contentScript.ts',
     },
     output: {
         filename: '[name].js',