Spam auto-ping

var b = new Audio('http://cdn-chat.sstatic.net/chat/meta2.mp3');
var e = /spam|\/smokedetector|low quality|offensive/i;
var h = /http/i;

var path = window.location.pathname.split('/');
if (path[1] == 'rooms' && path[2] == '89') {
  f();
}

function f() {
  var i, t;
  var a = document.getElementsByClassName('message');
  var m = a[a.length-1];
  if (m && !m.classList.contains('c')) {
    m.classList.add('c');
    if (m.children[1] && !m.parentNode.parentNode.classList.contains('mine')) {
      t = m.children[1].innerHTML;
      if (e.test(t) && h.test(t)) {
        b.play();
      }
    }
  }
  window.setTimeout(f,500);
}