Sends a single message from the extension's background scripts (or other privileged scripts, such as popup scripts or options page scripts) to any content scripts that belong to the extension and are running in the specified tab.

The message will be received in the content scripts by any listeners to the runtime.onMessage event. Listeners may then optionally send a response back to the background script using the sendResponse argument.

This is an asynchronous function that returns a Promise.


var sending = browser.tabs.sendMessage(
  tabId,                   // integer
  message,                 // any
  options                  // optional object


integer. ID of the tab whose content scripts we want to send a message to.
any. An object that can be serialized to JSON.
integer. Sends the message to a specific frame identified by frameId instead of all frames in the tab. Whether the content script is executed in all frames depends on the all_frames setting in the content_scripts section of manifest.json.

Return value

A Promise that will be fulfilled with the JSON response object sent by the handler of the message in the content script, or with no arguments if the content script did not send a response. If an error occurs while connecting to the specified tab or any other error occurs, the promise will be rejected with an error message. If several frames response to the message, the promise is resolved to one of answers.

Browser compatibility

ChromeEdgeFirefoxFirefox for AndroidOpera
Basic support Yes Yes14554 Yes

1. No response is sent after the receiving tab is refreshed if there is no `runtime.onMessage` listener.


Here's an example of a background script that sends a message to the content scripts running in the active tab when the user clicks the browser action. The background script also expect the content script to send a response:

// background-script.js
"use strict";

function onError(error) {
  console.error(`Error: ${error}`);

function sendMessageToTabs(tabs) {
  for (let tab of tabs) {
      {greeting: "Hi from background script"}
    ).then(response => {
      console.log("Message from the content script:");

browser.browserAction.onClicked.addListener(() => {
    currentWindow: true,
    active: true

Here's the corresponding content script:

// content-script.js
"use strict";

browser.runtime.onMessage.addListener(request => {
  console.log("Message from the background script:");
  return Promise.resolve({response: "Hi from content script"});

Example extensions


This API is based on Chromium's chrome.tabs API. This documentation is derived from tabs.json in the Chromium code.

Microsoft Edge compatibility data is supplied by Microsoft Corporation and is included here under the Creative Commons Attribution 3.0 United States License.

Document Tags and Contributors

 Last updated by: Alien426,