Php/docs/tutorial.oldcode
From Get docs
Now that PHP has grown to be a popular scripting language, there are a lot of public repositories and libraries containing code you can reuse. The PHP developers have largely tried to preserve backwards compatibility, so a script written for an older version will run (ideally) without changes in a newer version of PHP. In practice, some changes will usually be needed.
Two of the most important recent changes that affect old code are:
- The old
$HTTP_*_VARS
arrays are not available as of PHP 5.4.0. The following superglobal arrays were introduced in PHP » 4.1.0. They are:$_GET
,$_POST
,$_COOKIE
,$_SERVER
,$_FILES
,$_ENV
,$_REQUEST
, and$_SESSION
. - External variables are no longer registered in the global scope by default. In other words, as of PHP » 4.2.0 the PHP directive register_globals is off by default in
php.ini
. The preferred method of accessing these values is via the superglobal arrays mentioned above. Older scripts, books, and tutorials may rely on this directive beingon
. If it wereon
, for example, one could use$id
from the URLhttp://www.example.com/foo.php?id=42
. Whether on or off,$_GET['id']
is available.
For more details on these changes, see the section on predefined variables and links therein.