element.dispatchEvent is not a function

Question

I wrote a plugin , but whene Active ,disable Editor and in firebug Mozila below error Is shown

element.dispatchEvent is not a function   prototype.js:5457

and line 5457 prototype.js
  if (document.createEvent)
  5457:  element.dispatchEvent(event);
  else
  element.fireEvent(event.eventType, event);

  return Event.extend(event);
  }

but plugin work very good but disable Editor. What is the cause؟

Answer 1

Its cause the variable element has no function dispatchEvent. So you should check that element in this case is the one you expect, I doubt it. Probably you pass null/undefined or any other object but not a DOM element to this function.