function openEasyTicket(veranstaltungsId) {

    var easyTicketWindow, url, windowName, windowParams;
        
    if (veranstaltungsId === undefined) {
        return undefined;
    }
    
    url  = "https://www.easyticket.de/shop/index.php";
    url += "?affi=21&clear=true&noback=true";
    url += "&veranstnr=" + veranstaltungsId;
    windowName = "easy_ticket_" + veranstaltungsId;
    
    windowParams = "width=790,height=700,location=no,menubar=no,resizable=no,scrollbars=yes";
    
    easyTicketWindow = window.open(url, windowName, windowParams);
    easyTicketWindow.focus();
    
}