A view is defined by a view script, an HTML file that can contain PHP directives. The view script can use view helpers, which are classes that produce markup. View helpers are useful when the required markup is complex or used repeatedly in different locations. Place view helpers in the views/helpers folder under your module's folder.

Here is the skeleton of a view helper bar for the Foo module:

<?php
/**
 * View helper description
 *
 * @copyright   copyright info
 * @license     license info
 * @version     version info
 */
class Foo_View_Helper_Bar extends Zend_View_Helper_Abstract
{
    /**
     * Bar description
     *
     * @param   boolean  $capitalize  Whether the output should be in caps.
     * @return  string   the generated markup.
     */
    public function bar($capitalize = false)
    {
        return $capitalize ? 'BAR' : 'bar';
    }
}

To use this view helper in your view script:

The following line outputs bar:
<?= $this->bar(); ?>

The following line outputs BAR:
<?= $this->bar(true); ?>

For more details, see Section 14.4.1, “View Scripts” and the Zend Framework documentation.