(PHP 5 >= 5.2.0)
filter_input — Gets a specific external variable by name and optionally filters it
One of INPUT_GET, INPUT_POST, INPUT_COOKIE, INPUT_SERVER, INPUT_ENV, INPUT_SESSION (not implemented yet) and INPUT_REQUEST (not implemented yet).
Name of a variable to get.
Filter to apply. Defaults to FILTER_DEFAULT.
Associative array of options or bitwise disjunction of flags. If filter accepts options, flags can be provided in "flags" field of array.
Value of the requested variable on success, FALSE if the filter fails, or NULL if the variable_name variable is not set. If the flag FILTER_NULL_ON_FAILURE is used, it returns FALSE if the variable is not set and NULL if the filter fails.
Example #1 A filter_input() example
<?php
$search_html = filter_input(INPUT_GET, 'search', FILTER_SANITIZE_SPECIAL_CHARS);
$search_url = filter_input(INPUT_GET, 'search', FILTER_SANITIZE_ENCODED);
echo "You have searched for $search_html.\n";
echo "<a href='?search=$search_url'>Search again.</a>";
?>
上例的输出类似于：
You have searched for Me & son. <a href='?search=Me%20%26%20son'>Search again.</a>