Auto pokeback your Facebook Friends. Works on Greasemonkey, Vivaldi, Chromium, Chrome, Opera

pokebackbot.user.js

// ==UserScript==
// @name         Facebook Poke Bot
// @namespace    http://sagz.in/
// @version      1.1
// @description  Return FB Pokes
// @author       Sagar Savla
// @match        https://mtouch.facebook.com/pokes/*
// @grant        none
// ==/UserScript==

function updatePoke(){
	let pokebuttonclass = "_56bz _54k8 _56bs _56bu"; // mtouch.facebook.com
	//let pokebuttonclass = "_42ft _4jy0 _4jy3 _4jy1 selected _51sy"; //www.facebook.com
	var gg = document.getElementsByClassName(pokebuttonclass).length
	if(gg>0){
		for (var i in document.getElementsByClassName(pokebuttonclass)){
			let pbutton = document.getElementsByClassName(pokebuttonclass)[i];
			if (pbutton.innerHTML && pbutton.innerHTML.includes('Back')){
				pbutton.click();
				//console.log(pbutton.innerHTML);
			}
		}
	}
}

function randomIntFromInterval(min,max)
{
    return Math.floor(Math.random()*(max-min+1)+min);
}

// Randomize how quick to Poke back to make it seem human
(function loop() {
    var rand = randomIntFromInterval(10,1000)*1000;
    console.log(rand);
    setTimeout(function() {
            updatePoke();
            loop();  
    }, rand);
}());