Hello,

I am programming an user-defined page in S7-1500, and I am trying to access a local API with a JS script:

Hi AutoGen_5176452,

I ended up at the same point about one year ago (TIA V17) and I wasn't able to solve the "CORS-issue" on the S7-1500.

off-topic:
Frustrating errors even occured while calling ressources from the plc-standard-webpages via my selfmade plc-webpage on the same system (while only being authenticated through the modern "/api/jsonrpc"-endpoint and not additionally through the old-school standard-login-page...!)!

back-to-topic:
If you have full control (including all configs) over a real webserver (e.g. nginx on bare metal / virtual machine / dockered), you might be happy with a reversed solution:
Do your "web-dev" on the other machine and use the modern "/api/jsonrpc"-endpoint from that system for fetching the S7-1500-Data. Take a close look at the docs (buzzwords: "AUTH_TOKEN - mechanism" , initializing and incrementing "messageID" , ...).

Regards,

Axel