| FILTER_VALIDATE_INT | "int" | min_range , max_range | FILTER_FLAG_ALLOW_OCTAL, FILTER_FLAG_ALLOW_HEX | Validates value as integer, optionally from the specified range. |
| FILTER_VALIDATE_BOOLEAN | "boolean" | | FILTER_NULL_ON_FAILURE | Returns TRUE for "1", "true", "on" and "yes". Returns FALSE otherwise. If FILTER_NULL_ON_FAILURE is set, FALSE is returned only for "0", "false", "off", "no", and "", and NULL is returned for all non-boolean values. |
| FILTER_VALIDATE_FLOAT | "float" | decimal | FILTER_FLAG_ALLOW_THOUSAND | Validates value as float. |
| FILTER_VALIDATE_REGEXP | "validate_regexp" | regexp | | Validates value against regexp , a Perl-compatible regular expression. |
| FILTER_VALIDATE_URL | "validate_url" | | FILTER_FLAG_PATH_REQUIRED, FILTER_FLAG_QUERY_REQUIRED | Validates value as URL, optionally with required components. |
| FILTER_VALIDATE_EMAIL | "validate_email" | | | Validates value as e-mail. |
| FILTER_VALIDATE_IP | "validate_ip" | | FILTER_FLAG_IPV4, FILTER_FLAG_IPV6, FILTER_FLAG_NO_PRIV_RANGE, FILTER_FLAG_NO_RES_RANGE | Validates value as IP address, optionally only IPv4 or IPv6 or not from private or reserved ranges. |
| FILTER_SANITIZE_STRING | "string" | | FILTER_FLAG_NO_ENCODE_QUOTES, FILTER_FLAG_STRIP_LOW, FILTER_FLAG_STRIP_HIGH, FILTER_FLAG_ENCODE_LOW, FILTER_FLAG_ENCODE_HIGH, FILTER_FLAG_ENCODE_AMP | Strip tags, optionally strip or encode special characters. |
| FILTER_SANITIZE_STRIPPED | "stripped" | | | Alias of "string" filter. |
| FILTER_SANITIZE_ENCODED | "encoded" | | FILTER_FLAG_STRIP_LOW, FILTER_FLAG_STRIP_HIGH, FILTER_FLAG_ENCODE_LOW, FILTER_FLAG_ENCODE_HIGH | URL-encode string, optionally strip or encode special characters. |
| FILTER_SANITIZE_SPECIAL_CHARS | "special_chars" | | FILTER_FLAG_STRIP_LOW, FILTER_FLAG_STRIP_HIGH, FILTER_FLAG_ENCODE_HIGH | HTML-escape '"<>& and characters with ASCII value less than 32, optionally strip or encode other special characters. |
| FILTER_UNSAFE_RAW | "unsafe_raw" | | FILTER_FLAG_STRIP_LOW, FILTER_FLAG_STRIP_HIGH, FILTER_FLAG_ENCODE_LOW, FILTER_FLAG_ENCODE_HIGH, FILTER_FLAG_ENCODE_AMP | Do nothing, optionally strip or encode special characters. |
| FILTER_SANITIZE_EMAIL | "email" | | | Remove all characters except letters, digits and !#$%&'*+-/=?^_`{|}~@.[]. |
| FILTER_SANITIZE_URL | "url" | | | Remove all characters except letters, digits and $-_.+!*'(),{}|\\^~[]`<>#%";/?:@&=. |
| FILTER_SANITIZE_NUMBER_INT | "number_int" | | | Remove all characters except digits, plus and minus sign. |
| FILTER_SANITIZE_NUMBER_FLOAT | "number_float" | | FILTER_FLAG_ALLOW_FRACTION, FILTER_FLAG_ALLOW_THOUSAND, FILTER_FLAG_ALLOW_SCIENTIFIC | Remove all characters except digits, +- and optionally .,eE. |
| FILTER_SANITIZE_MAGIC_QUOTES | "magic_quotes" | | | Apply addslashes(). |
| FILTER_CALLBACK | "callback" | callback function or method | | Call user-defined function to filter data. |
