How should I be filtering/validating user inputted username/password...

[cgm225]

How should I be filtering/validating user inputted username and passwords?  Restated, before I even check to see if the provided username and password are ones I have in my database, how should I be checking their input (for mysql injections, etc.).

 

Should I be using the filter_var() function?  If so, with what setting?  Or should be be using a regex?  If so, again, what setting.

 

Thank you all in advance!

 

 

[mikefrederick]

mysql_real_escape_string