Facebook autopoker

autopoke.js

(function(w,d){
    var x = function(n,p) { return d.createExpression(p).evaluate(n).iterateNext(); };
    w.pokeBack = function() {
        pokeBack.id && window.clearTimeout(pokeBack.id);
        delete pokeBack.id;
        if(pokeBack.stopped) return;
        var a = x(d,'//a[contains(@class, "_4jy1") and contains(.,"Poke Back")]');
        if(a && ! a.pokedBack) {
            a.pokedBack = true;
            var who = x(a,'../../following-sibling::*[1]//a').innerText;
            a.click();
            console.log(who + ' -> ' + a.innerText);
        }
        pokeBack.id = w.setTimeout(pokeBack, a ? 1000: 3000);
    };
    pokeBack.stop = function() { this.stopped = true; }
})(window,document);