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Fired when a message is received from either an extension process or a content script.
Syntax
chrome.runtime.onMessage.addListener(function( message, // optional any sender, // MessageSender function() {...} // function ) {...}) chrome.runtime.onMessage.removeListener(listener) chrome.runtime.onMessage.hasListener(listener)
This API is also available as browser.runtime.onMessage.*
.
Events have three functions:
addListener(callback)
- Adds a listener to this event.
removeListener(listener)
- Stop listening to this event. The
listener
argument is the listener to remove. hasListener(listener)
- Checks whether a
listener
is registered for this event. Returnstrue
if it is listening,false
otherwise.
addListener syntax
Parameters
function
-
A callback function that will be called when this event occurs. The function will be passed the following arguments:
message
any
. The message sent by the calling script.
sender
- A
runtime.MessageSender
object representing the sender of the message.
sendResponse
- A function to call (at most once) to handle sending a response to the message. The argument should be any JSON-ifiable object. If you have more than one
onMessage
listener in the same document, then only one may send a response. This function becomes invalid when the event listener returns, unless you return true from the event listener to indicate you wish to send a response asynchronously (this will keep the message channel open to the other end untilsendResponse
is called). - This function returns a
boolean
. It should returntrue
from the event listener if you wish to callsendResponse
after the event listener returns.
Browser compatibility
The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Chrome | Edge | Firefox | Firefox for Android | Opera | |
---|---|---|---|---|---|
Basic support | Yes | Yes | 45.0 | 48.0 | 33 |
Compatibility notes
Edge
- 'MessageSender.tlsChannelId' is not supported.
Examples
This content script listens for click events in the web page. If the click was on a link, it messages the background page with the target URL:
// content-script.js
window.addEventListener("click", notifyExtension);
function notifyExtension(e) {
if (e.target.tagName != "A") {
return;
}
chrome.runtime.sendMessage({"url": e.target.href});
The background script listens for these messages and displays a notification using the notifications
API:
// background-script.js
chrome.runtime.onMessage.addListener(notify);
function notify(message) {
chrome.notifications.create({
"type": "basic",
"iconUrl": chrome.extension.getURL("link.png"),
"title": "You clicked a link!",
"message": message.url
});
}
Example add-ons
This API is based on Chromium's chrome.runtime
API. This documentation is derived from runtime.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.
// Copyright 2015 The Chromium Authors. All rights reserved. // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are // met: // // * Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above // copyright notice, this list of conditions and the following disclaimer // in the documentation and/or other materials provided with the // distribution. // * Neither the name of Google Inc. nor the names of its // contributors may be used to endorse or promote products derived from // this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.