Set URL of "like" button embedded in Facebook comments plugin

How can I set the URL of the "like" button embedded in the Facebook comments plugin?

The XFBML <fb:like>开发者_Python百科 tag has an href attribute, but the <fb:comments> tag lacks an equivalent attribute.

The url attribute seems to be deprecated. There are two new attributes returnurl and callbackurl but they have no effect on the LIKE url. Maybe it's a question of time, I don't know. I cretaed a new app, changed the og:url attribute but still no luck. It keeps on "liking" the same page.

updated for new version of Facebook comments plugin:

The new Facebook comments plugin no longer uses the xid attribute. Instead, the href attribute is used to both identify the comments box and associate a URL with it.

Compare new <fb:comments> to legacy <fb:comments>

original answer:

Figured it out while asking the question:

The <fb:comments> url attribute works like the <fb:like> href attribute.