php - Should I use regex for registration/login forms? -

is enough use mysql_real_escape_string , strip_tags username/password inputs or should include regex? website uses deprecated mysql.

for example:

if (!preg_match( "/^[\w-\.]+@([\w-]+\.)+[\w-]{0,3}$/",$_post['email'])) {     $error = "invalid email or password"; 

it's better validate email(inputs) before pass data mysql, fortunately, don't have use regex email validation, php have built-in function filter_var validation. faster regex validation.

syntax be:

if(! filter_var($_post['email'], filter_validate_email)) {     //email not valid,      $error = "invalid email or password"; }