| The returned status code in different scenarios | |
| allowed preflight response | status | | |
| ------- --------- -------- | ------ | | |
| 1 no x 400 | 0 | | |
| 2 no 200 x | 0 | | |
| 3 yes x 400 | 400 | | |
| 4 yes 200 400 | 400 | | |
| 5 yes 400 x | 0 | | |
| PASS 1. CORS disallowed, response status 400. | |
| PASS 2. CORS disallowed, preflight status 200. | |
| PASS 3. CORS allowed, response status 400. | |
| PASS 4. CORS allowed, preflight status 200, response status 400. | |
| PASS 5. CORS allowed, preflight status 400. | |