In a chat room, when someone pastes a certain word into the chat I want the browser to make a noise to alert me.

It seems like Tampermonkey should be able to do this, but I don't know how to start and searching turns up few, and inapplicable results.
(This other question seems close but the answer just plays a sound every 5 seconds no matter what!)

How can a userscript alert when a target word appears via AJAX?

In a chat room, when someone pastes a certain word into the chat I want the browser to make a noise to alert me.

It seems like Tampermonkey should be able to do this, but I don't know how to start and searching turns up few, and inapplicable results.
(This other question seems close but the answer just plays a sound every 5 seconds no matter what!)

How can a userscript alert when a target word appears via AJAX?

• javascript
• userscripts
• tampermonkey

1 Answer 1

Set up a MutationObserver to watch for the target word. Then use HTML5 Audio to play the desired sound.

This plete working script watches for the text "just now" and plays a mellifluous tune when that phrase appears:

// ==UserScript==
// @name     _Play sound when word appears on a page
// @include  https://stackexchange./questions?tab=realtime
// @grant    none
// ==/UserScript==
/* eslint-disable no-multi-spaces */

//-- Set the watched terms using the awesome power of regex.
var watchRegx = /\bjust now\b/i;
var alrtSound = new Audio ("data:audio/mp3;base64,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");

//-- Customize this next for your page or get lazy and use "body".
var cntnrNode = document.querySelector ("#mainArea");
if (typeof cntnrNode === "undefined")   console.error ("TM: Container node not found.");
else {
    var wordObsrv = new MutationObserver (alertOnWord);
    wordObsrv.observe (document.body, {childList: true, subtree: true} );
}
function alertOnWord (mutationRecords) {
    mutationRecords.forEach (muttn => {
        if (muttn.type === "childList"  &&  typeof muttn.addedNodes === "object") {
            muttn.addedNodes.forEach (newNode => {
                /*-- Restrict the kinds of nodes watched for better performance
                    and/or to avoid false positives.
                */
                if (newNode.nodeName === "DIV"  ||  newNode.nodeName === "SPAN"  ||  newNode.nodeName === "P") {
                    if (watchRegx.test (newNode.textContent) ) {
                        console.log ("Found new instance of target term!");
                        alrtSound.play ();
                    }
                }
            } );
        }
    } );
}

Install that script using Tampermonkey, or Violentmonkey, or similar and then visit the Stack Exchange Realtime page

You will hear the sound every time a new post appears -- which is usually several times per minute.