Script callback does not run when onerror fires

[Wombarly]

I'm trying to embed some scripts that people might have blocked in their browser (facebook sdk). I want to gracefully handle it when they do.

The issue is that the callback attribute isn't being called when the onerror event fires. I would like to have support for that, either by adding it to callback or adding a new onerror attribute.

Side question: Any reason why it's called callback and not onload when it only handles onload?