这是一个管理表单，我在其中添加了一个自定义选项卡，以便添加一些自定义字段到它。该表单工作正常。但我需要为我的一些字段添加field dependency。
如果字段zipbasedprice_isrange被设置为yes，那么我需要显示另外两个字段&如果它被设置为no，那么只应该显示一个字段。
我如何使用下面的表单实现这一点？
字段依赖关系应介于zipbasedprice_isrange、zipbasedprice_zip、zipbasedprice_zip_from_zip和zipbasedprice_zip_to_zip之间。

public function getFormHtml() {
        $form = new Varien_Data_Form(
            array('id' => 'edit_form', 'action' => $this->getData('action'), 'method' => 'post')
        );

            $this->getLayout()->createBlock('adminhtml/widget_form_renderer_element').
            $this->getLayout()->createBlock('adminhtml/widget_form_renderer_fieldset').
            $this->getLayout()->createBlock('adminhtml/widget_form_renderer_fieldset_element');

    $fieldset = $form->addFieldset('zipbasedprice_fields', array('legend' => Mage::helper('zipbasedprice')->__('Zip Based Price'))
    );

    $default_country = array('label' => 'IN', 'code' => 'India');

    $fieldset->addField('zipbasedprice_country', 'select', array(
                    'name' => 'zipbasedprice_country',
                    'label' => Mage::helper('zipbasedprice')->__('Country'),
                    'values'    => Mage::getModel('adminhtml/system_config_source_country')->toOptionArray(),
                    'required' => true,
                    'style' => 'width:275px',
                    'value' => $default_country,
                    'after_element_html' => '<p class="zipbased_comment" style="margin: 0 150px; padding: 3px;"><img style="margin-right: 4px;" src="http://zonepricing.innoexts.com/skin/adminhtml/default/default/images/note_bg.gif" /><small>select the country to apply price</small></p>',
         ));

    $regions = array();
    $regions['*'] = '*';
$regionList = Mage::getModel('directory/region')->getResourceCollection()->addCountryFilter('IN')->load();
foreach($regionList as $region){ $regions[$region['code']] = $region['default_name']; }

    $fieldset->addField('zipbasedprice_state', 'select', array(
        'name' => 'zipbasedprice_state',
        'label' => Mage::helper('zipbasedprice')->__('Region/State'),
        'values' => $regions,
        'required' => true,
        'style' => 'width:275px',
      ));

   $isRange = $fieldset->addField('zipbasedprice_isrange', 'select', array(
        'name' => 'zipbasedprice_isrange',
        'label' => Mage::helper('zipbasedprice')->__('Is Range?'),
        'values' => array(
            array(
                'value' => false,
                'label' => Mage::helper('zipbasedprice')->__('No'),
            ),
            array(
                'value' => true,
                'label' => Mage::helper('zipbasedprice')->__('Yes'),
            )
        ),
       'value' => false,
       'onchange' => 'onIsZipRangeChange()',
       'required' => false,
   'style' => 'width:275px',
      ));

    $fieldset->addField('zipbasedprice_zip', 'text', array(
        'name' => 'zipbasedprice_zip',
        'label' => Mage::helper('zipbasedprice')->__('Zip Code'),
        'class' => 'input',
        'required' => true,
    'style' => 'width:268px',
        'value' => '*',
        'maxlength' => 6,
     ));

     $fieldset->addField('zipbasedprice_zip_from_zip', 'text', array(
        'name' => 'zipbasedprice_zip_from_zip',
        'label' => Mage::helper('zipbasedprice')->__('Zip Code From'),
        'class' => 'input',
        'required' => true,
    'style' => 'width:268px',
        'value' => '*',
        'maxlength' => 6,
     ));

      $fieldset->addField('zipbasedprice_zip_to_zip', 'text', array(
        'name' => 'zipbasedprice_zip_to_zip',
        'label' => Mage::helper('zipbasedprice')->__('Zip Code To'),
        'class' => 'input',
        'required' => true,
    'style' => 'width:268px',
        'value' => '*',
        'maxlength' => 6,
     ));

    $fieldset->addField('zipbasedprice_price', 'text', array(
        'name' => 'zipbasedprice_price',
        'label' => Mage::helper('zipbasedprice')->__('Price'),
        'class' => 'input',
        'required' => true,
        'style' => 'width:268px',
        'value' => '0.00',
     ));

    $fieldset->addField('zipbasedprice_apply', 'select', array(
        'label' => Mage::helper('zipbasedprice')->__('Apply'),
        'name' => 'zipbasedprice_apply',
        'required' => false,
        'values' => array(
            array(
                'value' => 'fixed',
                'label' => Mage::helper('zipbasedprice')->__('Fixed'),
            ),
            array(
                'value' => 'percentage',
                'label' => Mage::helper('zipbasedprice')->__('Percentage'),
            )
        ),
        'required' => 1,
        'value' => 1,
        'style' => 'width:275px',
    ));

    return $form->toHtml();
}