<?php

$url = $_SERVER['SERVER_NAME'] . $_SERVER['REQUEST_URI'];
$parser = parse_url($url);
$queries = [];
if (isset($parser['query'])) {
    parse_str($parser['query'], $queries);
    unset($queries['islem']);
}
$queries['islem'] = 'ok';
$build = http_build_query($queries);
$new_url = $parser['path'] . '?' . $build;
echo $new_url;