PHP how to display errors after script finnished loading?

I already use:

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

at the beginning of my code. However, the error messages are displayed directly in the output (wich is a lot, so you can’t find the errors well).

How do I display all the errors that occured, after the script is done loading?