php 過濾字元函數 filter_var

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_EMAIL “validate_email” Validates value as e-mail.
FILTER_VALIDATE_FLOAT “float” decimal FILTER_FLAG_ALLOW_THOUSAND Validates value as float.
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_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_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 (according to ?, optionally with required components. Note that the function will only find ASCII URLs to be valid; internationalized domain names (containing non-ASCII characters) will fail.