JS object for toggling document.title text between current value and a temporary one at a specified interval. Also a method to stop/clear.

titleAnnoyance.js

function titleToggle( currTitle, tmpTitle, msInterval){
    var currTitle = currTitle;
    var tmpTitle = tmpTitle;
    var msInterval = msInterval;
    
    var timerID = -1;

    this.stop = function() {
        if ( timerID != -1) { 
            clearInterval(timerID); 
            document.title = currTitle; 
        } 
    }

    this.go = function() { 
        timerID = setInterval( switcheroo, msInterval, currTitle, tmpTitle); 
    }

    var switcheroo = function(currTitle, tmpTitle){
        if (document.title == currTitle) {
            document.title = tmpTitle;
        }
        else {
            document.title = currTitle;
        }
    }

    return this;
}

Although I dislike the purpose of this snippet, I do like how declaring the stop and go methods as part of this while not doing the same for the switcheroo function simulates the public/private scope of functions.

For additional context, you might also want to check out https://developer.mozilla.org/en-US/docs/Web/API/Page_Visibility_API.