To clarify , when I try to convert to using $.post, I'm getting:
XMLHttpRequest cannot load http://<esp_server>:<esp_http_port>/start. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access.
Usually if I have control over coding of HTTP server, I can fix this via header, but in this case, its inside the JAR.