See thread starting at https://lists.w3.org/Archives/Public/public-whatwg-archive/2017Oct/0013.html
Properly building the form submission requires knowing the submitter element. See https://html.spec.whatwg.org/#constructing-the-form-data-set and the "submitter" argument it takes.
If someone is trying to do the equivalent from a submit event, they can create a FormData from the form, but there's no way to figure out the submitter element at that point.
Ideally the submit event would expose the submitter element, if any, and the FormData constructor would take it as a second optional argument.
See thread starting at https://lists.w3.org/Archives/Public/public-whatwg-archive/2017Oct/0013.html
Properly building the form submission requires knowing the submitter element. See https://html.spec.whatwg.org/#constructing-the-form-data-set and the "submitter" argument it takes.
If someone is trying to do the equivalent from a submit event, they can create a FormData from the form, but there's no way to figure out the submitter element at that point.
Ideally the submit event would expose the submitter element, if any, and the FormData constructor would take it as a second optional argument.