function showtrainer( season , theme ) {
    var out = "NN" ;
    var url = "http://www.inline-club-hannover.de/databases/next_trainer.php" ;
    var xmlhttp;

    if (window.XMLHttpRequest) {
       xmlhttp = new XMLHttpRequest();
    } else if (window.ActiveXObject) {
       xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
    }

    if ( arguments.length > 0 ) {
        url += "?season=" ;
        url += encodeURI( arguments[0].replace(/ /g,'+') ) ;
        url += "&theme=" ;
        url += encodeURI( arguments[1].replace(/ /g,'+') ) ;
    }

    xmlhttp.open("GET", url , false);
    xmlhttp.send(null);

    if (xmlhttp.readyState == 4 ) {
        out = xmlhttp.responseText ;
    } else {
	out = 'Fehler beim Lesen der DB' ;
    }

    return out ;
}