raise event for invalid size or file type rather than hard coded alert

[devtrends]

would be nice if event was raised instead passing through filename. then could handle any way we like.

[LPology]

I like this idea. Do you mean creating a custom event, or adding callback functions like onSizeError() and onExtError() for handling those situations?

Adding callback functions is super easy - 4 lines of code total. I added a branch "develop" and changed the demo to use the callbacks (it has the same behavior with the alerts because I'm manually calling _errorMsg() but you could obv do anything).

Here's the code from the demo:

onExtError: function(filename, extension) { 
  this._errorMsg('ext');
},
onSizeError: function(filename, fileSize) {
  this._errorMsg('size');
}, 

An added bonus is that _errorMsg() can be removed, resulting in 29 fewer lines of code.

Thoughts?