WordPress: Add Facebook Like Button using functions.php

The Facebook Like button lets a user share contents with friends on Facebook. When the user clicks the Facebook Like button, a story appears in the user's friends' News Feed, with a link back to the original website.

[caption id="" align="alignnone" caption="Facebook Like Button"][/caption]

Append this code snippet to functions.php file in theme or child theme folder to add the Facebook Like Button.

function add_fb($content) {
    $fb = ''; // display only on single page.
    if (is_single()) {
        $fb = '<iframe src="http://www.facebook.com/plugins/like.php?href=';
        $fb .= urlencode(get_permalink(get_the_ID()));
        $fb .= '&amp;layout=standard&amp;show_faces=false&amp;width=450&amp;';
        $fb .= 'action=like&amp;colorscheme=light"';
        $fb .= ' style="border:none; overflow:hidden; width:450px; ';
        $fb .= 'height:60px"></iframe>';
    }
    
    // display before the content.
    return $fb . $content;
    
    // display after the content.
    // return $content . $fb;
}
    
add_filter('the_content', 'add_fb');

Please visit http://developers.facebook.com/docs/reference/plugins/like for more information on how to customize the Like Button.