- var_dump: documentation ( source)
- filter_var_array: documentation ( source)
<?php
$_POST = [ 'ajax_app' => 'messages', 'content' => 'ÄÜP=?', // ......
'mail' => [
// Hier ist der Hund begraben
],];
var_dump(filter_var_array($_POST,FILTER_SANITIZE_FULL_SPECIAL_CHARS));