CORS Javascript errors not handled

[WolfgangFahl]

Describe the bug
When doing #2759 and #2760 you end up with a non working enviroment.

To Reproduce
#2759 and/or #2760
You get

Expected behavior
javascript calls should work

Screenshots
you get misleading

claiming This query has timed out

Quellübergreifende (Cross-Origin) Anfrage blockiert: Die Gleiche-Quelle-Regel verbietet das Lesen der externen Ressource auf https://www.wikidata.org/w/api.php?origin=*&action=wbsearchentities&format=json&limit=50&continue=0&language=de&uselang=de&search=Q17012957&type=item. (Grund: CORS-Kopfzeile 'Access-Control-Allow-Origin' fehlt). Statuscode: 200.

Desktop (please complete the following information):
#2760

[WolfgangFahl]

is this the same as ad-freiburg#44?