related comboboxes

[docock]

Hi there,

I'm new to ajax and need to build something like this:
https://www.marktplaats.nl/syi/plaatsAdvertentie.html

The idea is that someone picks a value from the first combobox, and then a php script will fill the related values into a second combobox.

I haven't got a clue how to do this though.. I guess it's something with submitting the first combobox?

I've searched for hours for a tutorial on this without any luck.

Can anyone provide me an example on how to do this or give me a link to a proper tutorial ?

[sunfighter]

You might not have found it calling it a combobox. Try listbox.
A place to read http://www.hscripts.com/scripts/Java.../move-list.php
And code:

<table border=1 align=center valign=center>
<tr><td>From Group</td><td></td><td>To Group</td></tr>
<tr><td>
<select id=xxx multiple size=7 style="width:100;">

	<option>Pink</option>;
	<option>2</option>;
	<option>Green</option>;
	<option>5</option>;
	<option>Yellow</option>;

</select>
</td>
<td>
<input type=button value=">>" onclick=moveoutid()>
<input type=button value="<<" onclick=moveinid()>
</td>
<td>
<select id=yyy multiple size=7 style="width:100;">
<script type="text/javascript">
for(var j=0;j<to_array.length;j++)
{
	document.write('<option>'+to_array[j]+'</option>');
}
</script>
</select>
</td></tr>
</table>


<script type="text/javascript">

function moveoutid()
{
	var sda = document.getElementById('xxx');;
	var len = sda.length;
	var sda1 = document.getElementById('yyy');
	for(var j=0; j<len; j++)
	{
		if(sda[j].selected)
		{
			var tmp = sda.options[j].text;
			var tmp1 = sda.options[j].value;
			sda.remove(j);
			j--;
			var y=document.createElement('option');
			y.text=tmp;
			try
			{sda1.add(y,null);
			}
			catch(ex)
			{
			sda1.add(y);
			}
		}
	}
}


function moveinid()
{
	var sda = document.getElementById('xxx');
	var sda1 = document.getElementById('yyy');
	var len = sda1.length;
	for(var j=0; j<len; j++)
	{
		if(sda1[j].selected)
		{
			var tmp = sda1.options[j].text;
			var tmp1 = sda1.options[j].value;
			sda1.remove(j);
			j--;
			var y=document.createElement('option');
			y.text=tmp;
			try
			{
			sda.add(y,null);}
			catch(ex){
			sda.add(y);
			}

		}
	}
}
</script>