(PHP 5 >= 5.2.0, PECL filter:0.11.0)
filter_var — Filters a variable with a specified filter
Value to filter.
ID of a filter to use. Defaults to FILTER_SANITIZE_STRING.
Associative array of options or bitwise disjunction of flags. If filter accepts options, flags can be provided in "flags" field of array. For the "callback" filter, callback type should be passed.
Returns the filtered data, or FALSE if the filter fails.
Example#1 A filter_var() example
<?php
var_dump(filter_var('bob@example.com', FILTER_VALIDATE_EMAIL));
var_dump(filter_var('example.com', FILTER_VALIDATE_URL, FILTER_FLAG_SCHEME_REQUIRED));
?>
上例将输出：
string(15) "bob@example.com" bool(false)