Describe HTMLOptionsCollection's length tree mutation in terms of DOM

[annevk]

If the new value is greater, then n new option elements with no attributes and no child nodes must be appended to the select element on which the HTMLOptionsCollection is rooted, where n is the difference between the two numbers (new value minus old value). Mutation events must be fired as if a DocumentFragment containing the new option elements had been inserted.

Instead we should create a DocumentFragment, create and append n new option elements to it, and then append that DocumentFragment to the select element.

That avoids having to talk about mutation events altogether here. We should also have a test to ensure this is actually what happens in terms of mutation observers.

Note that a little bit below:

When the user agent is to set the value of a new indexed property or set the value of an existing indexed property for a given property index index to a new value value, it must run the following algorithm:

This is already done so basically the wording in that algorithm should be used here as well (possibly shared).

[Faizan711]

is this issue still open, if so i would like to be assigned for it.

[ainasanghi]

can you assign this to me?

[annevk]

We don't assign issues, but you're welcome to provide a PR.