Mozilla Firefox blocks(?) XHR requests?

Question

JavaScript

All the best! There is a page that is constantly open in the browser, in this case in Mozilla, in Chrome this problem has not yet been observed. Every 10 seconds an Ajax request is sent to the same domain. And so, after a while requests begin to be cached that-whether. That is, the browser says that the request was completed successfully, with a status of 200, but the data is returned irrelevant, and the request timings are 0 ms everywhere. This request does not reach the server, that is, the browser itself returns a response with the data that it received earlier. Tell me what could be the problem? Maybe in some browser settings?

Answer 1

In the HTTP headers returned by the server.
Since you guessed that the data is cached, why didn't you google it? Topic beaten.
What should have been done before creating the question:
What should have been done when creating the question:

• Describe how you tried to solve the problem and include the server response headers.
  
• Indicate that the server gives the necessary headers in your opinion, and there should be no caching according to the specifications.
  
• And that it is a paradox that you are unable to solve.