Pre-flighted JavaScript requests

PUT request with correct CORS setup


JavaScript code can make a cross-origin PUT request.

The pre-flight response must include the correctly configured Access-Control-Allow-Origin header. The response to the main request must include the same header.


  1. Press F12 to open browser Developer Tools
  2. Open Network tab and filter by path put-success
  3. Hit green button below and observe 1 pre-flight and 1 main request
View source on GitHub | Created by Tom Gregory