api.Document.selectstart_event - not supported by iOS (12)

[otacke]

What information was incorrect, unhelpful, or incomplete?

• The table lists iOS among the devices supporting the selectstart event. selectstart does not to be supported by iOS 12 at least.

• That behavior seems to be known at least since 2016, cmp. https://gist.github.com/robertknight/ad9f1bca8280b3fa325817aa3ed9935c, so other iOS versions are likely to be affected, too.

• CanIUse lists iOS 14 as minimum version, see https://caniuse.com/?search=selectstart

What did you expect to see?

I expected the selectstart event to be fired when starting to select text.

Did you test this? If so, how?

Yes. I used https://codepen.io/otacke/pen/wvodGZW to verify that the selectstart event is in fact not fired.

MDN page report details

• Query: api.Document.selectstart_event
• MDN URL: https://developer.mozilla.org/en-US/docs/Web/API/Document/selectstart_event
• Report started: 2021-02-16T19:32:09.578Z

[ddbeck]

This is closely related to #9144. Copying #9144 (comment) here:

Hi @otacke and thanks for raising this issue and the related #9143. Apparently selectstart has a number of issues associated with it.

A quick test shows that onselectstart does exist in the interface (e.g., "onselectstart" in document is true) but if it never fires fire, that's a bit misleading. I propose that we mark the feature as supported with a partial_implementation set to true and a note saying, "The selectstart event never fires and never invokes this handler."

To fix this, these need to be updated:

• onselectstart (partial implementation) in

  browser-compat-data/api/Document.json

  Line 10758 in e07c447

  "selectstart_event": {

• onselectstart (partial implementation) in

  browser-compat-data/api/GlobalEventHandlers.json

  Line 4155 in ee47fa5

  "onselectstart": {

• selectstart ("version_added": false)

  browser-compat-data/api/Document.json

  Line 10758 in e07c447

  "selectstart_event": {

I would welcome a PR from you (or another contributor) making these changes.

Thank you again!

(I'll duplicate this comment on the other issue, though this is not, strictly speaking, a duplicate.)