I would use
validate_username to protect username and other inputs from tags, octet, and others filters and conditions from
sanitize_user but these functions only remove these dangerous chars and does not warn the user to not use these chars.
Does it exist a wordpress function of the same kind as
validate_username that allow to warn and restrict user to use the same chars and conditions than those used in
validate_username function ?
Could you help me to write a regex which fulfills the same conditions as
validate_username to display error if one of conditions is positive.
And how I must do to add this regex
|%([a-fA-F0-9][a-fA-F0-9])| to this one
/^[A-Za-z0-9]*$/ I don't understand the use of
/ . In php.net this
| is use to say "or" .
For example this
/^[A-Za-z0-9]*$/ does not take into account octet (or hexadecimal ?) as it define here : WordPress
Knowing that hackers always discover solutions to hack what is to date the best solution to protect a registration and login form. If this last question is duplicate could you please post the link of existing response ?