Search icon change from corporex joomla template

?php
/**
 * @package     Joomla.Site
 * @subpackage  mod_search
 *
 * @copyright   Copyright (C) 2005 - 2013 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE.txt
 */

defined('_JEXEC') or die;
?>

<div class="search">
    <form action="<?php echo JRoute::_('index.php');?>" method="post">
        <input name="searchword" class="input-block-level" id="mod-search-searchword" type="text" placeholder="<?php echo $text; ?>" />
        <input type="hidden" name="task" value="search" />
        <input type="hidden" name="option" value="com_search" />
        <input type="hidden" name="Itemid" value="0" />
        <button class="btn-top-search" onclick="this.form.searchword.focus();">
            <!-- For change icon of search -->
            <i class="icon-search"></i>
        </button>
    </form>
</div>