function ajax_example_simplest

Basic AJAX callback example.

Simple form whose ajax-enabled 'changethis' member causes a text change in the description of the 'replace_textfield' member.

See Form API Tutorial

Related topics

File

ajax_example/ajax_example.module, line 305

Code

function ajax_example_simplest($form, &$form_state) {
    $form = array();
    $form['changethis'] = array(
        '#title' => t("Choose something and explain why"),
        '#type' => 'select',
        '#options' => array(
            'one' => 'one',
            'two' => 'two',
            'three' => 'three',
        ),
        '#ajax' => array(
            // #ajax has two required keys: callback and wrapper.
            // 'callback' is a function that will be called when this element changes.
'callback' => 'ajax_example_simplest_callback',
            // 'wrapper' is the HTML id of the page element that will be replaced.
'wrapper' => 'replace_textfield_div',
        ),
    );
    // This entire form element will be replaced whenever 'changethis' is updated.
    $form['replace_textfield'] = array(
        '#type' => 'textfield',
        '#title' => t("Why"),
        // The prefix/suffix provide the div that we're replacing, named by
        // #ajax['wrapper'] above.
'#prefix' => '<div id="replace_textfield_div">',
        '#suffix' => '</div>',
    );
    // An AJAX request calls the form builder function for every change.
    // We can change how we build the form based on $form_state.
    if (!empty($form_state['values']['changethis'])) {
        $form['replace_textfield']['#description'] = t("Say why you chose '@value'", array(
            '@value' => $form_state['values']['changethis'],
        ));
    }
    return $form;
}