Face book ask me to send my security code to protect and login to my account on facebook. the problem is how i get my security code?

Any social networking website , Facebook or Google or Yahoo or be it any one , will never ask for your security codes or passwords or log in ids for any purposes . never .
its a scam or phishing website , trying to dupe you into disclosing your personal and confidential credentials .
stay away from it .
if you have lost your password , try the account recovery options or contact the site Help staff ...