Add following to wp-config.php.
Activate Debug Mode
// Enable WP_DEBUG mode
define( 'WP_DEBUG', true );
// Enable Debug logging to the /wp-content/debug.log file
define( 'WP_DEBUG_LOG', true );
// Disable display of errors and warnings
define( 'WP_DEBUG_DISPLAY', true );
@ini_set( 'display_errors', 1 );
// Use dev versions of core JS and CSS files (only needed if you are modifying these core files)
define( 'SCRIPT_DEBUG', true );
define('WP_CACHE', false);
Deactivate Debug Mode
// Enable WP_DEBUG mode
define( 'WP_DEBUG', false );
// Enable Debug logging to the /wp-content/debug.log file
define( 'WP_DEBUG_LOG', false );
// Disable display of errors and warnings
define( 'WP_DEBUG_DISPLAY', false);
@ini_set( 'display_errors', 0 );
// Use dev versions of core JS and CSS files (only needed if you are modifying these core files)
define( 'SCRIPT_DEBUG', false );
define('WP_CACHE', true);
Key words: wp debug