Facebook tag (fb:...) [duplicate]

This question already has an answer here: Closed 11 years ago.

Possible Duplicate:

Create similar to fb:tag

In addition to my question:

Create similar to fb开发者_Python百科:tag

I would like to ask if someone knows how did Facebook create fb:tags using xmlns.

Just technologies and some short explanation.

I might find the answers that I am looking for the other question as well!

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xmlns is used just to make html valid xhtml, the functionality wont work just by adding fb:.. imported javascript is the on which process these tags