function div_auf() {
    f = document.getElementById("bild");
    f.style.visibility = 'visible';
}

function div_zu() {
    f = document.getElementById("bild");
    f.style.visibility = 'hidden';
}

function open(div, von, nach) {
    document.getElementById('i1').style.height = "0px";
    document.getElementById('i1').style.visibility = "hidden";
    document.getElementById('i2').style.height = "0px";
    document.getElementById('i2').style.visibility = "hidden";
    document.getElementById('i3').style.height = "0px";
    document.getElementById('i3').style.visibility = "hidden";
    document.getElementById('i4').style.height = "0px";
    document.getElementById('i4').style.visibility = "hidden";
    OpenDiv(div, von, nach)
}


function OpenDiv(div, von, nach) {

    if (div == 1) {
        var y = document.getElementById('i1');
    }
    if (div == 2) {
        var y = document.getElementById('i2');
    }
    if (div == 3) {
        var y = document.getElementById('i3');
    }
    if (div == 4) {
        var y = document.getElementById('i4');
    }    
    if (von <= nach) {
        var test = String(von) + "px";
        y.style.height = test;
        von = von + 10;
        window.setTimeout("OpenDiv(" + div + ", " + von + ", " + nach + ")", 1);
    }
    else {
        y.style.overflow = "hidden";
    }
    y.style.visibility = "visible";
    y.style.overflow = "hidden";
}
function CloseDiv(div, i, wert) {
    if (div == 1) {
        var y = document.getElementById('i1');
    }
    if (div == 2) {
        var y = document.getElementById('i2');
    }
    if (div == 3) {
        var y = document.getElementById('i3');
    }
    if (div == 4) {
        var y = document.getElementById('i4');
    }    
    y.style.overflow = "hidden";
    if (i >= wert) {
        var test = String(i) + "px";
        y.style.height = test;
        i = i - 10;
        window.setTimeout("CloseDiv(" + div + ", " + i + ", " + wert + ")", 1);
    }
}

function fade1(step) {
    step = step || 0;
    document.fl1.style.opacity = step / 100;
    document.fl1.style.filter = "alpha(opacity=" + step + ")"; // IE?
    step = step + 2;
    if (step <= 100) {
        window.setTimeout(function() { fade1(step); }, 1);
    }
}
function flattere(x) {
    if (x == 13) { x = 1; }
    document.fl1.src = bild[x].src;
    num = x + 1;
    fade1();
    window.setTimeout("flattere(num)", 2000);
    document.fl2.src = bild[x - 1].src;
}

function pruefen_anfrage() {
    var f = document.forms['anfrage'];
    var email = f.email.value;
    var name = f.name.value;
    var anfrage = f.anfrage.value;
    var ok = 'ja';

    if (email == '') {
        f.email.style.backgroundColor = "#a5d9ea";
        ok = 'nein';
    }
    if (name == '') {
        f.name.style.backgroundColor = "#a5d9ea";
        ok = 'nein';
    }
    if (anfrage == '') {
        f.anfrage.style.backgroundColor = "#a5d9ea";
        ok = 'nein';
    }    

    if (ok == 'nein') {
        document.getElementById('meldung').style.Color = "red";
        document.getElementById('meldung').style.visibility = "visible";
    }
    else {
        f.submit();
        document.getElementById('meldung').style.visibility = "hidden";
    }
}