Show button with JavaScript

I’m making a javascript to show a form on the website.

But nu I want to make a button to hide or show this form.
http://www.jcsl.nl/scouting/index.php?pagina=inschrijven&activiteit=houthakkersweekend

But the button doesn’t switch betwteen layout.

This is what I have.

javascript

<script langauge="javascript">
function showForm3(){
    document.getElementById('form3').style.display="block";
    document.getElementById('form3b').style.display="block";
    document.getElementById('form3z').style.display="none";    
    document.getElementById('form3zb').style.display="none";    
}

function showForm3z(){
    document.getElementById('form3z').style.display="block";
    document.getElementById('form3zb').style.display="block";
    document.getElementById('form3').style.display="none";    
    document.getElementById('form3b').style.display="none";    
}
</script>

buttons

<form id="form3" name="form3">
                    <input type="button" id="form3b" name="form3b"  value="Derde deelnemer laten zien." onclick="showForm3(); showForm3b();" '.$display3z.'/>&nbsp;
                    <input type="button" id="form3zb" name="form3zb"  value="Derde deelnemer niet laten zien" onclick="showForm3z(); showForm3zb();" '.$display3.'/> <br>
                    <br/>
                    </form>

form

<div id="form3z" name="form3z" '.$display3z.'>    
                            <div class="push100">&nbsp;</div>
                            <div class="push100">&nbsp;</div>
                            <div class="push80">&nbsp;</div>
                    </div>

<div id="form3" name="form3" '.$display3.'>    
                            <div class="push100">&nbsp;</div>
                            <div class="push100">&nbsp;</div>
                            <div class="push80">&nbsp;</div>
                    </div>

Problem is solved.

The problem was the javascript.

<script  type="text/javascript">
    function showForm3(){
        document.getElementById('form3').style.display="block";
        document.getElementById('button1').style.display="none";
        document.getElementById('form3z').style.display="none";    
        document.getElementById('button2').style.display="inline";    
    }
    
    function showForm3z(){
        document.getElementById('form3').style.display="none";    
        document.getElementById('button1').style.display="inline";    
        document.getElementById('form3z').style.display="block";
        document.getElementById('button2').style.display="none";
    }
    </script>