5b. Otherwise fall back (strip_tags())
{
Z_STRLEN_P(new_var) =
php_strip_tags(Z_STRVAL_P(new_var), Z_STRLEN_P(new_var),
NULL, NULL, 0);
}
Other example default filters might be:
- Deny the variable totally
- Use htmlentities()
- Strip everything not in [A-Za-z0-9]