event.preventDefault() vs. return false (no jQuery)

I wondered if event.preventDefault() and return false were the same. I have done some tests, and it seems that If the event handler is added using old model, for example elem.onclick = function(){ return false; }; Then, return false prevents default action, like event.preventDefault(). If the event handler is added using addEventListener, for example elem.addEventListener( 'click', function(e){ re