timokins

А он везде разный

var changeTitle = function() {
    this.title = function () {
        var title = document.title;
        document.title = (title == "hello" ? "" : "hello");
    }
};

changeTitle.prototype.start = function() {
    this.timer = setInterval(this.title, 1000);
};

changeTitle.prototype.stop = function() {
    clearInterval(this.timer)
};

var timerTitle = new changeTitle();
window.onblur = function() {
    timerTitle.start();
};
window.onfocus = function() {
    timerTitle.stop();
};

document.getElementById('toggle5').checked = false;