Cargar combo cuando se da click en un radio

$("select[name=idSites]").change(function(){

document.getElementById("elementos").disabled=true;

id = $('select[name=idSites]').val();

$("#elementos").load('utils/genera-selectElementos.php?id='+id);

document.getElementById("elementos").disabled=false;

        });




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require_once('../conexion/conexion.php');


session_start();

global $dbu;


if (isset($_GET['id'])) {

$query = "SELECT * FROM cat_equipos WHERE bandActivo = '1' AND idSites = '".$_GET['id']."' ORDER BY nombre";

$rs = $dbu->FetchOne($query,"obj");

if ( $rs ) {
echo '<optgroup label="Equipo">';
while ( !$rs->EOF ) {

echo '<option value="2-'.$rs->fields['idEquipos'].'">'.$rs->fields['nombre'].'</option>';

$rs->movenext();
}
}



$query = "SELECT * FROM cat_servidores WHERE bandActivo = '1' AND idSites = '".$_GET['id']."' ORDER BY nombre";

$rs = $dbu->FetchOne($query,"obj");

if ( $rs ) {
echo '<optgroup label="Servidores">';
while ( !$rs->EOF ) {

echo '<option value="3-'.$rs->fields['idServidores'].'">'.$rs->fields['descripcion'].'</option>';

$rs->movenext();
}
}


$query = "SELECT * FROM cat_aplicaciones WHERE bandActivo = '1' AND idServidores IN (SELECT idServidores FROM cat_servidores WHERE idSites = '".$_GET['id']."') ORDER BY nombre";

$rs = $dbu->FetchOne($query,"obj");

if ( $rs ) {
echo '<optgroup label="Aplicaciones">';
while ( !$rs->EOF ) {

echo '<option value="4-'.$rs->fields['idAplicaciones'].'">'.$rs->fields['nombre'].'</option>';

$rs->movenext();
}
}

 
}