Persist Selected Dropdown Options

[mjpr]

Hi,

I'm building an ajax/php/mysql application.
I have 3 dependent dropdowns. I use ajax to avoid the page reload on every selectbox change.

But if I reload the page after I drill down the 3 dropdowns, only the first dropdown maintains it's selected option, because I did it with php.

But I'm trying to do it for the 2nd and 3rd dropdown with javascript:

<code>
$marca = $_GET['IDMarca'];
echo "obj.options[obj.options.length] = new Option('-Seleccione-','0');\n";
while($resmodelo = mssql_fetch_array($queryModelos))
{
echo "obj.options[obj.options.length] = new Option('".$resmodelo['Descricao']."','".$resmodelo['IDModelo']."');\n";
echo "for (var i=0; i < obj.options.length; i++) {\n";
echo "alert('obj.options[i].selectedIndex.Value');";
echo " if (obj.options[i].selectedIndex.Value = ".$marca.") {\n";
echo " obj.options[i].selected = true;}\n";
echo "}\n";
}
</code>

But... it's not working. I get the error:
Error: obj.options[i].selectedIndex has no properties

Please help.

Mário

[Pepejeria]

Well, you dont show where obj is defined.

[mjpr]

My 1st and 2nd dropdowns have an onchange event defined. For example the 1st one (called ddlMarca) calls the function getModelos, which in turn calls createModelos.

Here's the code. Hope it helps to clear my question.


<code>
var ajax = new sack();

function getModelos(sel)
{
var IDMarca = sel.options[sel.selectedIndex].value;
//Empty model select box
document.getElementById('ddlModelo').options.length = 0;
if(IDMarca.length>0){
//Specifying which file to get
ajax.requestFile = 'getMV.php?IDMarca='+IDMarca;
//Specify function that will be executed after file has been found
ajax.onCompletion = createModelos;
ajax.runAJAX(); // Execute AJAX function
}
}

function createModelos()
{
var obj = document.getElementById('ddlModelo');
//Executing the response from Ajax as Javascript code
eval(ajax.response);
}

</code>