Missing comma in a sentence - makes it somewhat confusing to read

[JasonTheKitten]

Hello!
I was using the DOM Specification when I noticed that there was a missing comma.

This confused me for a moment, so I figured I would mention it, even though it probably is rather nitpicky
The location where the comma needs to be inserted is highlighted:

The following is super nit-picky, and probably does not matter at all, but once you add the comma to the sentence, it still is not perfect, as it then implies that the reason initEvent() is incapable of setting composed is that events have a constructor - which is not the case. Overall, I don't think this merits rewriting the sentence, so we should only focus on adding the comma to make it less confusing.