<?php
    $webinar_client_id = "1";
    $webinar_client_secret = "9EyOZBQT1C03JWV8eVlmstioTDM9BhzXHZ0Vehe7";

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, "https://neowebinar.cz/oauth/token");
    curl_setopt($ch, CURLOPT_POST, 1);

    curl_setopt($ch, CURLOPT_POSTFIELDS,"client_id=".$webinar_client_id."&client_secret=".$webinar_client_secret."&grant_type=client_credentials&scope=*");
    $output = curl_exec($ch);

    var_dump($output);
?>