What happens without CORS?

Example #1

GET https://node-cors-server.herokuapp.com/no-cors

(Example #1 should fail.)

Simple Requests (No Pre-Flight)

Example #2

GET https://node-cors-server.herokuapp.com/simple-cors

Example #3

HEAD https://node-cors-server.herokuapp.com/simple-cors

Example #4

POST https://node-cors-server.herokuapp.com/simple-cors

Complex Requests (Pre-Flight Required)

Example #5

DELETE https://node-cors-server.herokuapp.com/complex-cors