We have this

Changes (add/edit/delete) to captions and statement can't current be saved in IE11.
This is because IE11 doesn't set the Origin header for these cross-wiki requests, and we receive a 403.
The forms behave exactly like they do when there's another error, except that no error message shows up (because there's no actual error message in the response body)

We want this

Ideally, SDoC also works in IE11 (because MediaWiki officially still support it).
But this could be a pretty tough nut to crack (more info on SO), so we might have to settle for showing some error message, so that IE11 users at least know something went wrong.

Acceptance Criteria

• It is possible to submit captions and statement changes in IE11 (prefered)

or

• In IE11, the JS widgets are not loaded, essentially not even providing edit tools (backup plan)

or

• It is impossible to submit caption and statement changes in IE11, but an error message is displayed clarifying this (last resort, but we should probably do this anyway for unidentified errors)