Change to check on createEvent instead of attachEvent

Change to check on createEvent instead of attachEvent in firelistener, since the function actually uses createEvent.

We had a problem in IE8 which surprisingly used the firelistener function for modern browsers. In other words, the W3C_MODEL was true. That was because we have a polyfill for attachEvent. But we do not have a polyfill for createEvent, which is actually the method in use in firelistener.

Is it a bug or is it another reason why you check for attachEvent, but uses the createEvent?

The pull request assumes it is a bug and therefore checks for createEvent instead.

Best regards,
Maiken