The title pretty much say it all. I'm trying to update an attribute value with a POST call. I have POST method allowed in the web API setting and my page make a sucesful OPTION post before using POST but somehow it refuse to take the POST call. It tell me only PUT and GET are allowed. I tried using the PUT method but I run into CORS refusal. Even if I remove the CORS check from the browser it still tell me I can't modify the attribute "Substituted", which make the request fail since PUT need to modify every attributes.
Is it even possible to modify only the value of an attribute?
Here's my code: