Emit a loaded event when loading is complete

[Primigenus]

In order to implement a fallback in the form of <q42 ...>my fallback here</q42>, the element needs to indicate when it has completed loading.

I'm trying to get this to work:

<q42><img src="q42.png" alt="Q42"></q42>

...such that the image is hidden if the script loads correctly, but if it for some reason fails to load, it falls back to just showing the image. But since the Q42Logo script doesn't indicate when it's done, there's no way to accomplish this.

[Primigenus]

(Even better than emitting a loaded event would just be implementing support for a fallback by default, so that whatever is inside the element is shown unless the script loads)