$_POST¶
An associative array of variables, transmitted to the current script via the HTTP POST method, with the MIME types application/x-www-form-urlencoded or multipart/form-data.
The received values are all strings or arrays. They are strings by default, and other scalar types needs a casting. The values are arrays when the URL uses the [] format.
$_POST is a superglobal : it is always available, in every scope.
Values inside $_POST are always strings, or arrays.
<?php
// POST x=1
$_POST['x'] === '1';
// POST y=abc
$_POST['y'] === 'abc';
// POST z[]=def
// POST z[]=ghi
$_POST['z'] === array('def', 'ghi');
?>