function addEvent(obj, evType, fn) {
  if (obj.addEventListener) {
    obj.addEventListener(evType, fn, true);
    return true;
  } else if (obj.attachEvent) {
    var r = obj.attachEvent("on"+evType, fn);
    return r;
  } else {
    return false;
  }
}

function whatCorrector() {
  var replaces=0;
  while (document.body.innerHTML.indexOf('##'+'AT##')!=-1 && replaces<10000) {
    document.body.innerHTML=document.body.innerHTML.replace('##'+'AT##',String.fromCharCode(64));
    replaces++;
  }
}
addEvent(window, 'load', whatCorrector);