How do I get PHP errors to display?

I have checked my PHP ini file (php.ini) and display_errors is set and also error reporting is E_ALL. I have restarted my Apache webserver.

I have even put these lines at the top of my script, and it doesn't even catch simple parse errors. For example, I declare variables with a "$" and I don't close statements";". But all my scripts show a blank page on these errors, but I want to actually see the errors in my browser output.

error_reporting(E_ALL);
ini_set('display_errors', 1);

What is left to do?

DEV environment

This always works for me:

ini_set('display_errors', '1');
ini_set('display_startup_errors', '1');
error_reporting(E_ALL);

However, this doesn't make PHP to show parse errors occurred in the same file. Also, these settings can be overridden by PHP. In these cases the only way to show those errors is to modify your php.ini (or php-fpm.conf) with this line:

display_errors = on

(if you don't have access to php.ini, then putting this line in .htaccess might work too):

php_flag display_errors 1

PROD environment

Note that above recommendation is only suitable for the DEV environment. On a live site it must be

display_errors = off
log_errors = on

And then you'll be able to see all errors in the error log. See Where to find PHP error log

AJAX calls

In case of AJAX call, on a DEV server, open DevTools (F12), then Network tab. Then initiate the request which result you want to see, and it will appear in the Network tab. Click on it and then the Response tab. There you will see the exact output.

While on a live server just check the error log all the same.