get last active time
// ==UserScript==
// @name FB Mobile: Last Online Activity
// @namespace http://tampermonkey.net/
// @version 0.1
// @description get last active time
// @author You
// @match https://m.facebook.com/messages/read/*
// @grant none
// ==/UserScript==
(function() {
'use strict';
var el = document.querySelector(".fbLastActiveTimestamp abbr");
if (el)
{
var json = JSON.parse(el.getAttribute("data-store"));
var ltime = +json.time;
function gettime(t){
function lz(x){x<<=0;var p=x<10?"0"+x:x+"";return p=="00"?"":p+":";}
var d=lz(t/86400);
var h=lz(t/3600%24);
var m=lz(t/60%60);
var s=lz(t%60);
var r = d+h+m+s;
return r.slice(0,-1);
}//
var ttime = gettime(new Date/1e3-ltime), lat = new Date(ltime*1e3);
var ne = document.createElement("span");
ne.innerHTML = `<abbr>`+ttime + " (" + lat + ")"+`</abbr>`;
ne.setAttribute("class", "fbLastActiveTimestamp mfss fcg");
ne.setAttribute("style", "display:block");
el.parentNode.appendChild(ne);
console.warn("Elapsed:", ttime);
console.warn("Last Active Date:", lat);
}
// Your code here...
})();