function set_export_source($source)
{
    require '../inc/export.inc.php';
    if (in_array($source, array_keys(get_export_sources()))) {
        $GLOBALS['s_export']['source']['option'] = $source;
    }
}
                                <?php 
    echo get_indexed_selectlist('dt_export_format', get_export_formats(), $s_export['format'], FALSE, array('onChange' => 'replaceExportFormatOptions(this.value);'));
    ?>
                            </td>
                        </tr>
                    </table>
                </td>
                <td valign="top">
                    <table class="table table-bordered">
                        <tr>
                            <th align="left" colspan="2">Source</th>
                        </tr>
                        <tr>
                            <td valign="top">
                                <?php 
    echo get_indexed_selectlist('dt_export_source', get_export_sources(), $s_export['source']['option'], FALSE, array('onChange' => 'setExportSource(this.value);'));
    ?>
                            </td>
                            <td>
            <span id="dt_export_source_table_span" style="display:<?php 
    $s_export['source']['option'] == 'table' ? print 'block' : (print 'none');
    ?>
;">
              <?php 
    echo get_table_selectlist('dt_export_source_table', array('select'), $s_export['source']['table'], TRUE);
    ?>
            </span>
            <span id="dt_export_source_dbtables_span" style="display:<?php 
    $s_export['source']['option'] == 'db' ? print 'block' : (print 'none');
    ?>
;">