Dubbele dropdownbox icm javascript geeft een probleem.

	<!-- drop down #1, selection drives content in drop-down #2 -->
	<!-- onChange event does not fire if value does not change  -->
    <!-- you may want to try using the onClick event instead         -->
	<select name="Land" id="Land" onChange="return ContinentListOnChange()">
	<?php
	$query  = "SELECT * from spots_tbl group by Land";
	$result = mysql_query($query);
	while($row = mysql_fetch_assoc($result))
	{ 
	echo '<option value="' . $row['Land'] . '">' . $row['Land'] . '</option>';
	}	
	
	?>
	</select>
	<!-- drop down #2, list contents depend on value selected in drop-down #1 -->
    <!-- code in the file js/AjaxCode.js will populate this drop-down list                  -->
    Selecteer de plaats:
    <BR>
	<select name="countrylist" id="countrylist" >
	</select>

</html>

<!-- drop down #1, selection drives content in drop-down #2 -->
	<!-- onChange event does not fire if value does not change  -->
    <!-- you may want to try using the onClick event instead         -->
	<select name="Land" id="Land" onChange="return ContinentListOnChange()">
	<?php
	$query  = "SELECT * from spots_tbl group by Land";
	$result = mysql_query($query);
	while($row = mysql_fetch_assoc($result))
	{ 
	echo '<option value="' . $row['Land'] . '">' . $row['Land'] . '</option>';
	}	
 
	?>
	</select>
	<!-- drop down #2, list contents depend on value selected in drop-down #1 -->
    <!-- code in the file js/AjaxCode.js will populate this drop-down list                  -->
    Selecteer de plaats:
    <BR>
	<select name="countrylist" id="countrylist" >
	</select>
 
</html>

// populate the contents of the country dropdown list
function PopulateCountryList(countryNode)
{
    var countryList = document.getElementById("countryList");
	// clear the country list 
	for (var count = countryList.options.length-1; count >-1; count--)
	{
		countryList.options[count] = null;
	}

	var countryNodes = countryNode.getElementsByTagName('country');
	var idValue;
	var textValue; 
	var optionItem;
	// populate the dropdown list with data from the xml doc
	for (var count = 0; count < countryNodes.length; count++)
	{
   		textValue = GetInnerText(countryNodes[count]);
		idValue = countryNodes[count].getAttribute("id");
		optionItem = new Option( textValue, idValue,  false, false);
		countryList.options[countryList.length] = optionItem;
	}
}

// populate the contents of the country dropdown list
function PopulateCountryList(countryNode)
{
    var countryList = document.getElementById("countryList");
	// clear the country list 
	for (var count = countryList.options.length-1; count >-1; count--)
	{
		countryList.options[count] = null;
	}
 
	var countryNodes = countryNode.getElementsByTagName('country');
	var idValue;
	var textValue; 
	var optionItem;
	// populate the dropdown list with data from the xml doc
	for (var count = 0; count < countryNodes.length; count++)
	{
   		textValue = GetInnerText(countryNodes[count]);
		idValue = countryNodes[count].getAttribute("id");
		optionItem = new Option( textValue, idValue,  false, false);
		countryList.options[countryList.length] = optionItem;
	}
}

echo '<option value="' . $row['Land'] . '">' . $row['Land'] . '</option>';

echo '<option value="' . $row['Land'] . '">' . $row['Land'] . '</option>';

echo "<option value=\"" . $row['Land'] . "\">" . $row['Land'] . "</option>";

echo "<option value=\"" . $row['Land'] . "\">" . $row['Land'] . "</option>";

	$query  = "SELECT * from spots_tbl where country = '$filter'";

$query  = "SELECT * from spots_tbl where country = '$filter'";

	$query  = "SELECT DISTINCT area from spots_tbl where country = '$filter'"; 

$query  = "SELECT DISTINCT area from spots_tbl where country = '$filter'";

	var countryNodes = countryNode.getElementsByTagName('country');

var countryNodes = countryNode.getElementsByTagName('country');