I can not understand why my page is not cached?

Question

PHP

Tried all options, nothing works.
Here is one option:

header("Cache-Control: public");
header("Expires: " . date("r", time() + 3600));
echo "<h1>", date("H:i:s"), "</h1>";

Answer 1

header("Cache-control: public");
header("Expires: " . gmdate("D, d M Y H:i:s", time() + 60*60*24) . " GMT"); // на сутки

Answer 2

Please describe the problem in more detail.

Answer 3

This is not enough. In any case, the browser sends a request to the server with the question - has the data changed? The server sends a Status Code header with a value of 304 Not Modified and the browser loads the page from the cache if the data received from the browser matches.
Personally, I recommend using etag - it's more convenient.
ps I wanted to write that you must write this logic in the code, the server does not track php without you.

Answer 4

Guys, give a couple of links to sensible things that you can read or watch