php - how facebook grab link information? -


when type link in facebook can see title, site name, description , images of link. know facebook use 2 ways grab link information:

1-using og tags

2-using meta tags inside head tag of html.

but there websites example don't have og tags or meta tags description , facebook display description , title.

my question, if website doesn't has og tags or meta tags, description information?

when post link example in facebook post http://php.net/ can see description appear although cann't find og:description tags or meta tags in sourse of page. if post link of question facebook can see question apear, how facebook this?

by analyzing site, imperfect procedure, facebook recommends using og tags site appears in post want to.


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