The Original AddEvent

addevent.js

/*
Original tutorial URL from 2001
"Crossbrowser DOM Scripting: Event Handlers"
https://scottandrew.com/weblog/articles/cbs-events

Archive.org link:
https://web.archive.org/web/20051124085135/https://scottandrew.com/weblog/articles/cbs-events

"AddEvent considered harmful"
https://www.quirksmode.org/blog/archives/2005/08/addevent_consid.html
*/

function addEvent(obj, evType, fn, useCapture){
  if (obj.addEventListener){
    obj.addEventListener(evType, fn, useCapture);
    return true;
  } else if (obj.attachEvent){
    var r = obj.attachEvent("on"+evType, fn);
    return r;
  } else {
    alert("Handler could not be attached");
  }
}