A quick quide on how to use htaccess file (is configured in php.ini) to display or logPHP errors or change error reporting level.
To simply display errors add the following line at the top of your .htaccess file
php_flag display_errors on
To enable error loggin to a file add the line below, replacing DIR_PATH with filepath of your log file. Make sure the file is writable by your webserver.
php_flag log_errors on php_value error_log /DIR_PATH/PHP_errors.log
The next line enables logging or displaying of all errors. You can change the integer to suite your error logging requirements. Use the tool at the following URL to calculate the error loging value: http://www.bx.com.au/tools/ultimate-php-error-reporting-wizard
php_value error_reporting 32767
You should also add the following directive to you .htaccess file if you intend to place PHP_errors.log within publicly accessible web folder. However I'd recommend placing the log file in a folder that is not accessible via a browser
<Files PHP_errors.log> Order allow,deny Deny from all Satisfy All </Files>