What is xid in facebook comment api?

I am trying to put facebook comment in my wordpress blog for each post. I want to pass the url of the post as an xid but it doesn't work. I want to do that so that i will be able to collect the comments for each post sepa开发者_开发百科rately.

Let me know if there is any other way to collect the comments for post separately.

You're correct to use the XID as a unique identifier for each post. According to the documentation, the XID can consist of: "alphanumeric characters (Aa-Zz, 0-9), hyphens (-), percent (%), period (.), and underscores (_)".

Instead of using the URL, try passing in the unique ID of each post if you have access to it from WordPress. If that isn't an option, use PHP to url-encode your URL.