PHP Notice

Dalam PHP ketika anda menjalankan sebuah script, terkadang muncul pesan Notice padahal sebelumnya tidak pernah muncul.
Hal ini bisa terjadi ketika anda mencobanya bukan di server hosting melainkan di komputer anda sendiri atau biasanya disebut localhost.
Perlu anda ketahui, notice ini bukanlah error yang patut anda khawatirkan.
Ada beberapa programmer ngeyel yang menyarankan untuk membuat script 100% bebas dari notice dengan alasan takut akan celah keamaan.
Hal ini 100% tidak ada hubungannya, karena notice hanya muncul pada production level, yaitu ketika anda menggunakan localhost untuk membuat script anda.
Ketika script sudah siap dihostingkan, maka notice otomatis akan menghilang, karena server hosting menggunakan default value sehingga tidak menampilkan pesan notice.

Untuk mengatur pesan notice tersebut, anda bisa mencari file php.ini pada folder tempat anda menginstall php di komputer anda.
Kemudian anda cari “error_reporting”, nanti anda akan menemukan yang seperti berikut

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Error handling and logging ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

; This directive informs PHP of which errors, warnings and notices you would like
; it to take action for. The recommended way of setting values for this
; directive is through the use of the error level constants and bitwise
; operators. The error level constants are below here for convenience as well as
; some common settings and their meanings.
; By default, PHP is set to take action on all errors, notices and warnings EXCEPT
; those related to E_NOTICE and E_STRICT, which together cover best practices and
; recommended coding standards in PHP. For performance reasons, this is the
; recommend error reporting setting. Your production server shouldn't be wasting
; resources complaining about best practices and coding standards. That's what
; development servers and development settings are for.
; Note: The php.ini-development file has this setting as E_ALL | E_STRICT. This
; means it pretty much reports everything which is exactly what you want during
; development and early testing.
;
; Error Level Constants:
; E_ALL             - All errors and warnings (includes E_STRICT as of PHP 6.0.0)
; E_ERROR           - fatal run-time errors
; E_RECOVERABLE_ERROR  - almost fatal run-time errors
; E_WARNING         - run-time warnings (non-fatal errors)
; E_PARSE           - compile-time parse errors
; E_NOTICE          - run-time notices (these are warnings which often result
;                     from a bug in your code, but it's possible that it was
;                     intentional (e.g., using an uninitialized variable and
;                     relying on the fact it's automatically initialized to an
;                     empty string)
; E_STRICT          - run-time notices, enable to have PHP suggest changes
;                     to your code which will ensure the best interoperability
;                     and forward compatibility of your code
; E_CORE_ERROR      - fatal errors that occur during PHP's initial startup
; E_CORE_WARNING    - warnings (non-fatal errors) that occur during PHP's
;                     initial startup
; E_COMPILE_ERROR   - fatal compile-time errors
; E_COMPILE_WARNING - compile-time warnings (non-fatal errors)
; E_USER_ERROR      - user-generated error message
; E_USER_WARNING    - user-generated warning message
; E_USER_NOTICE     - user-generated notice message
; E_DEPRECATED      - warn about code that will not work in future versions
;                     of PHP
; E_USER_DEPRECATED - user-generated deprecation warnings
;
; Common Values:
;   E_ALL & ~E_NOTICE  (Show all errors, except for notices and coding standards warnings.)
;   E_ALL & ~E_NOTICE | E_STRICT  (Show all errors, except for notices)
;   E_COMPILE_ERROR|E_RECOVERABLE_ERROR|E_ERROR|E_CORE_ERROR  (Show only errors)
;   E_ALL | E_STRICT  (Show all errors, warnings and notices including coding standards.)
; Default Value: E_ALL & ~E_NOTICE
; Development Value: E_ALL | E_STRICT
; Production Value: E_ALL & ~E_DEPRECATED
; http://php.net/error-reporting
error_reporting = E_ALL & ~E_NOTICE

Kemudian ubah nilainya sesuai keinginan anda (default/development/production).

Notice: Use of undefined constant index – assumed ‘index’ in

Notice: Undefined index: index in

Notice: Undefined variable: variable in

Contoh script

<?php
echo $variable[index];
echo $_GET[index];
?>