Check if user already likes fanpage

Question

Is it possible to check if a user already likes my facebook fanpage from my website with Javascript or PHP?

EDIT: I need a solution, so the user doesn't need to authenticate / allow some persmissions first

Answer 1

In case you are OK with user giving the permissions, for a PHP based website it can be done this way easily:

1- Create a new Facebook app here.

2 - Download Facebook PHP SDK from here. Extract the files and place it in the same folder with the file in which you will paste the code given below!

3 - Get your Facebook Page ID using this tool.

4 - Generate Facebook like box code for your page from here.

After 1, 2, 3 and 4 steps are complete, you can check if user has liked a page or not with the following code:

<?php
    require('facebook.php');
    $config = array(
         'appId' => 'your facebook app id',
         'secret' => 'your facebook app secret code',

        'allowSignedRequest' => false
    );
    $facebook = new Facebook($config);
    $user_id = $facebook->getUser();
    if (isset($user_id)) {
        try {           
            $likes = $facebook->api('/me/likes/your_facebook_page_id_here', 'GET');             

            if (!empty($likes['data'])) // if user has liked the page then $likes['data'] wont be empty otherwise it will be empty
            {
                echo 'Thank you for liking our fan page!';                   

            }
            else {
                echo 'You have not liked our fan page! Like it now:';
                ?>                   
                <iframe src="//www.facebook.com/plugins/likebox.php?href=https%3A%2F%2Fwww.facebook.com%2Fchillopedia&amp;width&amp;height=290&amp;colorscheme=light&amp;show_faces=true&amp;header=true&amp;stream=false&amp;show_border=true&amp;appId=1392604484339363" scrolling="no" frameborder="0" style="border:none; overflow:hidden; height:290px;" allowTransparency="true"></iframe> //replace this with your own Facebook like box code
                <?php
            }
        } catch (FacebookApiException $e) {
            $login_url = $facebook->getLoginUrl();
            echo '<a href="' . $login_url . '">Please click here to login into your Facebook account.</a>';
            error_log($e->getType());
            error_log($e->getMessage());
        }
    } else {
        $login_url = $facebook->getLoginUrl();
        echo '<a href="' . $login_url . '">Please lick here to login into your Facebook account</a>';
    }
    ?>

The user will click on the "Please click here to login into your Facebook account." text which will redirect it to Facebook app permissions page, once user allows the permission to your app the code will fetch user's data and will display the likebox if user hasn't liked your fan page.