I haven't learned this before and don't understand it.

Question

$_SERVER['PHP_SELF']; I don’t know what the following PHP_SELF means

Answer 1

$_SERVER['PHP_SELF'] The file name of the currently executing script, related to the document root.

For example, using $_SERVER['PHP_SELF'] in a script at http://example.com/test.php/foo.bar will result in /test.php/foo.bar.

https://www.runoob.com/php/php-superglobals.html

Answer 2

OK, thanks

Answer 3

$_SERVER['PHP_SELF']

The file name of the currently executing script is related to the document root.

For example, using $_SERVER['PHP_SELF'] in a script at http://example.com/test.php/foo.bar will result in /test.php/foo.bar.

https://www.runoob.com/php/php-superglobals.html

Answer 4

This is a fixed parameter, just remember it