How to remove this symbol?

Question

PHP

The site has a registration in which the user specifies his nickname and password, but the nickname has this symbol �. How to remove it?

Answer 1

1. Filter nicknames using a list of valid characters.
2. What transformations do you do with the nickname before the output?

Answer 2

add the u modifier to the regex that handles validation before database entry

Answer 3

You better show how you get a nickname into the database. Or maybe you cut something with the help of substr ()? If so, then change to mb_