function vkExUnit_add_follow($content)
{
    $postType = vkExUnit_get_post_type();
    if (is_single() && $postType['slug'] == 'post') {
        $options = vkExUnit_get_sns_options();
        if (!$options['enableFollowMe']) {
            return $content;
        }
        if (isset($options['followMe_title']) && $options['followMe_title']) {
            $title = $options['followMe_title'];
        } else {
            $title = __('Follow me', 'vkExUnit') . '!';
        }
        // https://about.twitter.com/resources/buttons#follow
        $follow_html = '';
        $fbPageUrl = isset($options['fbPageUrl']) ? $options['fbPageUrl'] : '';
        $twitterId = isset($options['twitterId']) ? $options['twitterId'] : '';
        $follow_html .= '<div class="veu_followSet veu_contentAddSection">' . "\n";
        $follow_html .= '<h3 class="followSet_title">' . $title . '</h3>';
        if ($fbPageUrl) {
            $follow_html .= '<div class="follow_btn fb-like" data-href="' . esc_url($options['fbPageUrl']) . '" data-layout="button" data-action="like" data-show-faces="false" data-share="true"></div>' . "\n";
        }
        if ($twitterId) {
            $follow_html .= '<div class="follow_btn follow_twitter"><a href="https://twitter.com/' . esc_html($options['twitterId']) . '" class="twitter-follow-button" data-show-count="false" data-lang="ja" data-show-screen-name="false">@' . esc_html($options['twitterId']) . '</a></div>' . "\n";
        }
        $follow_html .= '<div class="follow_btn follow_feedly"><a href="http://cloud.feedly.com/#subscription/feed/' . home_url() . '/feed/" target="blank"><img id="feedlyFollow" src="http://s3.feedly.com/img/follows/feedly-follow-rectangle-volume-small_2x.png" alt="follow us in feedly" width="66" height="20"></a></div>' . "\n";
        $follow_html .= '</div><!-- [ /.followSet ] -->' . "\n";
        $content .= $follow_html;
    }
    // if ( $postType == 'post' && is_single() ) :
    return $content;
}
function exUnit_print_fbId_script()
{
    ?>
<div id="fb-root"></div>
<?php 
    $options = vkExUnit_get_sns_options();
    $fbAppId = isset($options['fbAppId']) ? $options['fbAppId'] : '';
    ?>
<script>(function(d, s, id) {
    var js, fjs = d.getElementsByTagName(s)[0];
    if (d.getElementById(id)) return;
    js = d.createElement(s); js.id = id;
	js.src = "//connect.facebook.net/ja_JP/sdk.js#xfbml=1&version=v2.3&appId=<?php 
    echo esc_html($fbAppId);
    ?>
";
    fjs.parentNode.insertBefore(js, fjs);
}(document, 'script', 'facebook-jssdk'));</script>
	<?php 
    //endif;
}
<h3><?php 
echo __('SNS Settings');
?>
</h3>
<?php 
$options = vkExUnit_get_sns_options();
/*-------------------------------------------*/
/*  SNS
/*-------------------------------------------*/
?>
<div id="snsSetting" class="sectionBox">

<!-- OGP hidden -->
<table class="form-table">
<tr>
<th><?php 
_e('facebook application ID', 'vkExUnit');
?>
</th>
<td><input type="text" name="vkExUnit_sns_options[fbAppId]" id="fbAppId" value="<?php 
echo esc_attr($options['fbAppId']);
?>
" /><br />
<span>[ <a href="https://developers.facebook.com/apps" target="_blank">&raquo; <?php 
_e('I will check and get the application ID', 'vkExUnit');
?>
</a> ]</span><br />
<?php 
_e('* If an application ID is not specified, neither a Like button nor the comment field displays and operates correctly.', 'vkExUnit');
?>
<br />