function golwebdes_seminar_output () {

include('golwebdes_conf.inc.php');

setlocale(LC_TIME, 'de_DE.utf8');

global $wpdb;

$seminare = $seminare_gki;

if (isset($_GET['semid'])) { // Einzelseminar
    $sql = "SELECT * FROM ".$seminare." WHERE id=".$_GET['semid'];
    $result = $wpdb->get_row($sql) or die(mysql_error());
    $html = '<div class="container-fluid">';

    $kateg = $result->kategorie;
    $html .= '<div class="col-sm-12"><div class="row" style="margin-bottom:3%;">
    <div class="col-sm-3">
    <img src="/pics/icon-workshops-indien.gif" alt="" class="img-responsive">
    </div>
    <div class="col-sm-9" style="padding-left:3%;">';
    $html .= '<p><span class="small">'.$seminarkategorien[$kateg].'</span><br><span style="font-weight:bold;">'.$result->titel.'</span></p>';
    $html .= '<p>'.$result->kurzinfo.'</p>';
    $html .= '<p>'.$result->beschreibung.'</p>';
    $html .= '<p>'.$result->inhalt.'</p>';


    /**** BEGINN - Erzeugen der Termine: Ort Datum Anmeldelink ***/
    $termine='';

    /* 1 */
    if ($result->ort1!='')
        $ort1 = $result->ort1;

    if ($result->datum_beginn1!=0) {
        if ($result->datum_ende1!=0) {
            if (date("m",$result->datum_beginn1) == date("m",$result->datum_ende1))
                $datum1 = date("j.",$result->datum_beginn1)."/".date("j.",$result->datum_ende1).strftime(" %B %Y", strtotime(date("m/d/Y", $result->datum_beginn1)));
            }
        else
            $datum1 = date("j.",$result->datum_beginn1).strftime(" %B %Y", strtotime(date("m/d/Y", $result->datum_beginn1)));
        }
    else
        $datum1 = "Termin folgt.";

    if ($result->datum_ende1 !=0 && $result->datum_ende1 >= time())
        $termin1 = "<strong>".$ort1."</strong> ".$datum1." <a href="#" class="anmeldung" onclick="window.open('seminaranmeldung.php?s=".$result->id."&o=1','anmeldung','').focus();return false;" >zur Anmeldung</a>";
    else if ($result->datum_ende1 ==0 && $result->datum_beginn1 !=0 && $result->datum_beginn1 >= time())
        $termin1 = "<strong>".$ort1."</strong> ".$datum1." <a href="#" onclick="window.open('seminaranmeldung.php?s=".$result->id."&o=1','anmeldung','').focus();return false;" class="anmeldung">zur Anmeldung</a>";
    else if ($result->datum_beginn1 ==0)
        $termin1 = $ort1." ".$datum1;

    $termine = $termine.$termin1.'<br>';


    /* 2 */
    if ($result->ort2!='')
        $ort2 = $result->ort2;

    if ($result->datum_beginn2!=0) {
        if ($result->datum_ende2!=0) {
            if (date("m",$result->datum_beginn2) == date("m",$result->datum_ende2))
                $datum2 = date("j.",$result->datum_beginn2)."/".date("j.",$result->datum_ende2).strftime(" %B %Y", strtotime(date("m/d/Y", $result->datum_beginn2)));
            }
        else
            $datum2 = date("j.",$result->datum_beginn2).strftime(" %B %Y", strtotime(date("m/d/Y", $result->datum_beginn2)));
        }
    else
        $datum2 = "Termin folgt.";

    if ($result->datum_ende2 !=0 && $result->datum_ende2 >= time())
        $termin2 = "<strong>".$ort2."</strong> ".$datum2." <a href="#" class="anmeldung" onclick="window.open('seminaranmeldung.php?s=".$result->id."&o=2','anmeldung','').focus();return false;"  >zur Anmeldung</a>";
    else if ($result->datum_ende2 ==0 && $result->datum_beginn2 !=0 && $result->datum_beginn2 >= time())
        $termin2 = "<strong>".$ort2."</strong> ".$datum2." <a href="#" class="anmeldung" onclick="window.open('seminaranmeldung.php?s=".$result->id."&o=2','anmeldung','').focus();return false;"  >zur Anmeldung</a>";
    else if ($result->datum_beginn2 ==0)
        $termin2 = $ort2." ".$datum2;


    $termine = $termine.$termin2.'<br>';

<div id="ajax-register-modal">
    <input type="text" id="ajax-username" placeholder="<?php _e( 'Username', 'text-domain' ); ?>"/>
    <input type="password" id="ajax-password" placeholder="<?php _e( 'Password', 'text-domain' ); ?>"/>
    <span id="register-modal-send"><?php _e( 'Register', 'text-domain' ); ?></span>
</div>

jQuery('#YourLinkID').click(function($){
    $('#ajax-register-modal').toggle();
});

jQuery('#register-modal-send').click(function($){
    registerTheUser();
});

function registerTheUser(){
    // Get the field values for username and password
    var username = $('#ajax-username').val();
    var password = $('#ajax-password').val();
    // Send them to server via AJAX
    jQuery.ajax({
        type: 'GET',
        url: 'REST URL HERE',
        data: { ajaxUsername: username , ajaxPassword: password},
    });
}

add_action( 'rest_api_init', function () {
    //Path to REST route for registration
    register_rest_route( 'LarryG001/v2', '/ajax_registration/', array(
            'methods' => 'GET', // I suggest using POST
            'callback' => 'register_the_user' // Callback PHP function
    ) );
});

function register_the_user(){
    // Get the username and password
    $username = $_GET['ajaxUsername'];
    $password = $_GET['ajaxPassword'];
    // A basic creation of user based on username and password. Email is optional
    $id = wp_create_user( $username, $password, $email );
    // Return the ID of the new user
    return $id;
}

http://example.com/wp-json/LarryG001/v2/ajax_registration/