如何在facebook Graph API中使用Javascript进行评论

How do i unlike a comment which was previously liked using the Graph API?

According to the Graph API docs you can send a DELETE request to /comment_id/likes and that'll clear the like.

You issue a DELETE request to the LIKES endpoint for the Facebook object that you're trying to remove a like from. You need a valid user session access token (or an offline access token) in order to accomplish this. It's also worth noting that you can't like/unlike PAGES on Facebook using this method, that is a process that the user must manually complete (via visiting the page or clicking a like button from their news feed, or even using the like button social widget.)

Below is an example of how to remove a like from an object using the Facebook PHP SDK.

<?php
$fb = new Facebook(array(
    'appId' => FB_APP_ID,
    'secret' => FB_APP_SECRET,
    'cookie' => true
));

$session = $fb->getSession();

if (empty($session))
{
    $loginUrl = $fb->getLoginUrl();
    echo "<script>window.top.location='{$loginUrl}';</script>";
    exit;
}

$fb_liked_object = '123123_123123_123123'; //put the object id you want to delete here

try
{
    $status = $fb->api("/{$fb_liked_object}/likes", 'DELETE');

    if ($status)
    {
        echo "Success, Unliked!";
    }
    else
    {
        echo "Could not unlike this object.";
    }
}
catch (Exception $e)
{
    var_dump($e);
}