Filter out non-allowed parameters in the request input and protect parameter values against XSS.

sanitize_input_array.php

<?php
/**
 * Filter out non-allowed parameters in the request input and protect parameter values against XSS
 *
 * @param int $type INPUT_GET, INPUT_POST, INPUT_COOKIE, INPUT_SERVER, INPUT_ENV
 * @param array $allowed_params
 * @link https://www.php.net/manual/en/function.filter-input-array.php
 * @return array
 */
function sanitize_input_array($type, array $allowed_params) {
    return filter_input_array($type, array_fill_keys($allowed_params, array(
        'filter' => FILTER_CALLBACK,
        'options' => function ($value) {
            return trim(strip_tags($value));
        }
    )));
}
/*
Usage:
http://example.com/index.php?full_name=`Shorty`%20O'Reilly&email=%20<script>alert('xss');</script>%20&array[][]=<b>10</b>&submit=Send
$allowed_params = array('submit', 'full_name', 'email', 'array', 'other');
$get = sanitize_input_array(INPUT_GET, $allowed_params);
$post = sanitize_input_array(INPUT_POST, $allowed_params);
Result:
var_dump($get);
array(6) {
  'submit' =>
  string(4) "Send"
  'email' =>
  string(13) "alert('xss');"
  'array' =>
  array(1) {
    [0] =>
    array(1) {
      [0] =>
      string(2) "10"
    }
  }
  'full_name' =>
  string(17) "`Shorty` O'Reilly"
  'other' =>
  NULL
}
*/