Export field in admin configuration in magento
devm.com.np

// system.xml
<export translate="label">
   <label>Export</label>
   <frontend_model>module/adminhtml_system_config_form_field_export</frontend_model>
   <sort_order>50</sort_order>
   <show_in_default>0</show_in_default>
   <show_in_website>1</show_in_website>
   <show_in_store>0</show_in_store>
 </export>
 
// config.xml
<admin>
     <routers>
        <adminhtml>
            <args>
                <modules>
                    <Company_Module before="Mage_Adminhtml">Company_Module</Company_Module>
                </modules>
            </args>
        </adminhtml>
    </routers>
</admin>
 
<?php
 
class Company_Module_Block_Adminhtml_System_Config_Form_Field_Export extends Mage_Adminhtml_Block_System_Config_Form_Field

{
    
      protected function 
_getElementHtml(Varien_Data_Form_Element_Abstract $element)
    {
        
$this->setElement($element);

        
$buttonBlock $this->getLayout()->createBlock('adminhtml/widget_button');
        
        
$params = array(
            
'website' => $buttonBlock->getRequest()->getParam('website')
        );
        
         
$data = array(
            
'label'     => Mage::helper('adminhtml')->__('Export CSV'),
        
        
'onclick'   => 'setLocation(\''.Mage::helper('adminhtml')->getUrl("*/*/export"$params) . '\' )',
            
'class'     => '',
        );

        
$html $buttonBlock->setData($data)->toHtml();

        return 
$html;
    }
    
    
}

 
?>
 
 
 
<?php
class Company_Module_System_ConfigController   extends Mage_Adminhtml_Controller_Action
{    
    public function 
exportAction()
    {

        
$fileName   'products.csv';

        
$gridBlock  $this->getLayout()->createBlock('catalog/product_grid');
        
$content    $gridBlock->getCsvFile();
        
$this->_prepareDownloadResponse($fileName$content);
    }
    
}
?>