// http://stackoverflow.com/a/2490876
var event;
if (document.createEvent) {
  event = document.createEvent("HTMLEvents");
  event.initEvent("dataavailable", true, true);
} else {
  event = document.createEventObject();
  event.eventType = "dataavailable";
}

event.eventName = eventName;
event.memo = memo || { };

if (document.createEvent) {
  element.dispatchEvent(event);
} else {
  element.fireEvent("on" + event.eventType, event);
}