Passing arguments via AHAH in Drupal

Drupal 6.22

I have an empty page except for a form that takes two input values and, when submitted, must display the result of a query based on that. The result may be displayed in a new window or on the same page, the only requirement is that the form is still easily accessible. I've tried to use AHAH to achieve this but I haven't found a way to send along the input.

This is what I have now:

function somemodule_menu()
{
    $items['somemodule/js'] = array(
        'page callback' => 'somemodule_js',
        'access arguments' => array('access content'),
        'type' => MENU_CALLBACK,
    );

    return $items;
}

function somemodule_form()
{
    $form = array();
    $format = 'd/m/Y';
    $default = 'Y-m-d 00:00:00';

    $form['from'] = array(
        '#type' => 'date_popup',
        '#title' => t('From'),
        '#default_value' => date($default),
        '#date_format' => $format,
        '#required' => TRUE
    );

    $form['to'] = array(
        '#type' => 'date_popup',
        '#title' => t('To'),
        '#default_value' => date($default, mktime(0, 0, 0, date('n') + 6)),
        '#date_format' => $format,
        '#required' => TRUE
    );

    $form['submit'] = array(
        '#type' => 'submit',
        '#value' => t('Send'),
        '#ahah' => array(
            'path' => 'somemodule/js',
            'wrapp开发者_StackOverflow社区er' => 'entry-wrapper',
            'method' => 'replace',
            'progress' => array(
                'type' => 'bar',
                'message' => t('Please wait...')
            )
        )
    );

    return $form;
}

function somemodule_js()
{
    return drupal_json(array('status' => TRUE, 'data' => "some data"));
}

This submits the form and correctly inserts some data into entry-wrapper. I know that I can make the following changes:

function somemodule_menu()
{
    $items['somemodule/js/somevar'] = ...
}

function somemodule_form()
{
    ...
    $form['submit'] = array(
        '#ahah' => array(
            'path' => 'somemodule/js/wharrgarbl',
    ...
}

function somemodule_js($string)
{
    return drupal_json(array('status' => TRUE, 'data' => $string));
}

and I'll get wharrgarbl back, but a static value rather defeats the point.

Is there a way to access the form state of somemodule_form from within that function after the first submission or am I going about this entirely the wrong way?

---

I don't know how I missed it but the signature for hook form is hook_form(&$node, $form_state). PHP's forgiveness can be a curse sometimes. Anyway, a completely unrelated Google search turned up this question about multistep forms, which is what I ended up doing.