Skip Navigation
LibreWolf @lemmy.ml streetfestival @lemmy.ca

How to set timezone without disabling ResistFingerprinting

I recently migrated to Librewolf from Firefox due to Mozilla's recent blunder of covertly adding adware to their browser.

I like the ResistFingerprinting feature for added privacy, but enabling it seems to set my browser time to GMT instead of ET, with most times on webpages (which refer to browser time) ahead by several hours as a result.

Can I define my desired timezone in the browser settings so I don't have to pick one or the other between a correct browser time and better privacy? TIA :D!

5
5 comments

  • I have a similar requirement and use a self-written script in Tampermonkey, in which I falsify the wrong time (GMT) to the correct time just for websites I have previously defined. Specifically, I overwrite the newDate function on these.

    This means that Librewolf always displays the wrong time (GMT) by default, except for websites I want to have the correct time (which just are a few) without the need to disable RFP.

    • Any chance you could share your script? I've tried a few browser extensions to solve this but they never seem to work on the sites where I actually need them. Your approach sounds way better!

      • Yes, of course. You will have to adapt it to your time zone, as the German time zone is currently hardcoded. If I had known back then that I would be sharing this at some point, I would have tried harder. 😅

        // ==UserScript==
// @name         Spoof Timezone
// @namespace    http://tampermonkey.net/
// @version      0.1
// @license      GPL-3.0
// @description  Overwrites the Date object to use the German time zone
// @author       dvb
// @match        *://*.foo.com/*
// @match        *://*.bar.com/*
// @match        *://*.foobar.com/*
// @match        https://webbrowsertools.com/timezone/
// @grant        none
// @run-at       document-start
// ==/UserScript==

(function() {
    'use strict';

    const originalDate = Date;

    function isSummerTime(now) {
        const month = now.getMonth() + 1; // January is 0, so +1
        const day = now.getDate();
        const hour = now.getHours();

        if (month > 3 && month < 10) { // Summer time is from April to September
            return true;
        } else if (month === 3 && day >= 29 && hour >= 2) { // Last Sunday in March at 2 o'clock
            return true;
        } else if (month === 10 && day <= 25 && hour < 3) { // Last Sunday in October at 3 o'clock
            return true;
        }

        return false;
    }

    function getGermanDate(...args) {
        const now = new originalDate(...args);
        const germanTimeZoneOffset = isSummerTime(now) ? -120 : -60; // German time zone is UTC+1 (+2 during summer time)
        if (args.length === 0) {
            return new originalDate(now.getTime() + (now.getTimezoneOffset() - germanTimeZoneOffset) * 60000);
        } else {
            return now;
        }
    }

    // Overwrite the newDate function
    const newDate = function(...args) {
        return getGermanDate(...args);
    };

    // Copy the prototypes and static methods
    Object.setPrototypeOf(newDate, originalDate);
    Object.setPrototypeOf(newDate.prototype, originalDate.prototype);
    for (const prop of Object.getOwnPropertyNames(originalDate)) {
        if (typeof originalDate[prop] === 'function') {
            newDate[prop] = originalDate[prop].bind(originalDate);
        } else {
            Object.defineProperty(newDate, prop, Object.getOwnPropertyDescriptor(originalDate, prop));
        }
    }

    // Overwrite Date objects
    Date = newDate;
    window.Date = newDate;
})();