(PHP 5 >= 5.2.0, PHP 7, PHP 8)
filter_has_var — Checks if variable of specified type exists
$input_type, string $var_name): bool
input_type
One of INPUT_GET, INPUT_POST,
INPUT_COOKIE, INPUT_SERVER, or
INPUT_ENV.
var_nameName of a variable to check.
Returns true on success or false on failure.