function unten(){
 document.getElementById('content').scrollTop = document.getElementById('cal_table').offsetHeight-130;
}

function def_vars(){
    filter1 = 0;
    create_cal();
}

function cal_combo_change(){
    document.getElementById('cal_text').style.visibility='hidden';
    filter1 = document.getElementById('cal_combo').selectedIndex;
    create_cal();
}

function year_forw(){
    document.getElementById('cal_text').style.visibility='hidden';
    datum = datum+31449600;
    create_cal();
}

function year_back(){
    document.getElementById('cal_text').style.visibility='hidden';
    datum = datum-31449600;
    create_cal();
}

function mon_forw(){
    document.getElementById('cal_text').style.visibility='hidden';
    datum = datum+2620800;
    create_cal();
}

function mon_back(){
    document.getElementById('cal_text').style.visibility='hidden';
    datum = datum-2620800;
    create_cal();
}

function create_cal(){
                    //erstellen des requests
     var req = null;

    try{
        req = new XMLHttpRequest();
    }
    catch (ms){
        try{
            req = new ActiveXObject("Msxml2.XMLHTTP");
        }
        catch (nonms){
            try{
                req = new ActiveXObject("Microsoft.XMLHTTP");
            }
            catch (failed){
                req = null;
            }
        }
    }

    if (req == null)
          alert("Error creating request object!");

      //anfrage erstellen (GET, url ist localhost,
      //request ist asynchron

      switch (filter1) {
      case 0:
        filtercmd = 'Alles';
        break;
      case 1:
        filtercmd = 'Kart';
        break;
      case 2:
        filtercmd = 'BMX';
        break;
      case 3:
        filtercmd = 'Feier';
        break;
      case 4:
        filtercmd = 'Clubmeisterschaft';
        break;
      case 5:
        filtercmd = 'Ausfahrt';
        break;
      case 6:
        filtercmd = 'Wintertraining';
        break;
      case 7:
        filtercmd = 'Sonstiges';
        break;
    }

      req.open("POST", './cal.php?date='+datum+'&filter1='+filtercmd, true);
    //Beim abschliessen des request wird diese Funktion ausgef�hrt
    req.onreadystatechange = function(){
        switch(req.readyState) {
                case 4:
                if(req.status!=200) {
                    alert("Fehler:"+req.status);
                }else{
                    document.getElementById('cal').innerHTML = req.responseText;
                    document.getElementById('cal_combo').selectedIndex = filter1;
                }
                break;

                default:
                    return false;
                break;
            }
        };

      req.setRequestHeader("Content-Type",
                          "application/x-www-form-urlencoded");
    req.send(null);
}