Суперглобальные переменные
I strongly recommend against using globals at all possible. It's a bad programming practice, and you're better off using references and passing them on construct to use them in the $this context. If you're worried about parameters, you can simply use an associative array to store any passed variables to it. Overall, the main idea is to avoid using globals.
http://www.phpit.net/article/using-globals-php/
Is a good article detailing other reasons why using the global scope is a very bad idea.
$GLOBALS
$GLOBALS — References all variables available in global scope
Описание
An associative array containing references to all variables which are currently defined in the global scope of the script. The variable names are the keys of the array.
Примеры
Пример #1 $GLOBALS example
<?php
function test() {
$foo = "local variable";
echo '$foo in global scope: ' . $GLOBALS["foo"] . "\n";
echo '$foo in current scope: ' . $foo . "\n";
}
$foo = "Example content";
test();
?>
Результатом выполнения данного примера будет что-то подобное:
$foo in global scope: Example content $foo in current scope: local variable
Примечания
Замечание: This is a 'superglobal', or automatic global, variable. This simply means that it is available in all scopes throughout a script. There is no need to do global $variable; to access it within functions or methods.
Замечание: Variable availability
Unlike all of the other superglobals, $GLOBALS has essentially always been available in PHP.
add a note
User Contributed Notes$GLOBALS
Pyornide
17-Oct-2008 12:43
17-Oct-2008 12:43
ravenswd at yahoo dot com
12-Aug-2008 11:02
12-Aug-2008 11:02
Keep in mind that $GLOBALS is, itself, a global variable. So code like this won't work:
<?php
print '$GLOBALS = ' . var_export($GLOBALS, true) . "\n";
?>
This results in the error message: "Nesting level too deep - recursive dependency?"