php - how can show error or warning in the page -

i have site in server.

because of settings, no error or warning displaying in page

how can change setting, using .htaccess file

simple, can add line php so:

<?php ini_set('display_errors','on');  ?> 

or add following lines htaccess:

php_flag display_errors on php_flag html_errors on 

i try stay away modifying htaccess file if part of site in production.

hope helps