Focus Page.user.js

Focus Page.user.js

// ==UserScript==
// @name     Focus
// @include  *
// @run-at   document-start
// @grant    unsafeWindow
// ==/UserScript==

unsafeWindow.document.hasFocus = function () {return true;};
// visibilitychange events are captured and stopped
document.addEventListener("visibilitychange", function(e) {
    e.stopImmediatePropagation();
}, true, true);

// document.visibilityState always returns false
Object.defineProperty(Document.prototype.wrappedJSObject, "hidden", {
    get: exportFunction(function hidden() { return false; }, window.wrappedJSObject),
    enumerable: true, configurable: true
});

// document.visibilityState always returns "visible"
Object.defineProperty(Document.prototype.wrappedJSObject, "visibilityState", {
    get: exportFunction(function visibilityState() { return "visible"; }, window.wrappedJSObject),
    enumerable: true, configurable: true
});

window.onbeforeunload = function(){
            return 'Are you sure you want to leave?';
        };