I'm trying to do an HTTP request with the following headers:
headers.append("Content-Type", "text/xml; charset=utf-8");
headers.append("SOAPAction", "<domain>/<function-name>");
which triggers a preflight request.
On the server side I'm running IIS 7.5.x and an .asmx service. I can get everything to work if I run Chrome without web security. I already set "Access-Control-Allow-Headers" and "Access-Control-Allow-Origin", reducing the "error volume". I so wish there was a web.config setting for this to just make it work.
See also this answer but in the context of AngularJS: https://stackoverflow.com/a/33662315/1613772