I cannot convince why I've encountered following error even I've added following code in NodeJS/ExpressJS.
XMLHttpRequest cannot load http://localhost:9000/polymer/105724/apply.
Response to preflight request doesn't pass access control check: No
'Access-Control-Allow-Origin' header is present on the requested
resource. Origin 'http://localhost:8080' is therefore not allowed
res.setHeader("Access-Control-Allow-Headers", "X-Requested-With, Content-Type");
You also need to allow
OPTIONS method. Browser sends an
OPTIONS call before the actual call so if
OPTIONS is not allowed next call will not be made.