php man page for filter_input

FILTER_INPUT(3) 							 1							   FILTER_INPUT(3)

filter_input - Gets a specific external variable by name and optionally filters it

SYNOPSIS
       mixed filter_input (int	$type, string  $variable_name, [int  $filter = FILTER_DEFAULT], [mixed	$options])

DESCRIPTION
PARAMETERS
	      o $type
		- One of INPUT_GET, INPUT_POST, INPUT_COOKIE, INPUT_SERVER, or INPUT_ENV.

	      o $variable_name
		- Name of a variable to get.

	      o $filter
		-  The ID of the filter to apply. The "Types of filters" manual page lists the available filters.  If omitted, FILTER_DEFAULT will
		be used, which is equivalent to FILTER_UNSAFE_RAW. This will result in no filtering taking place by default.

	      o $options
		- Associative array of options or bitwise disjunction of flags. If filter accepts options, flags can be provided in "flags"  field
		of array.

RETURN VALUES
	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 FIL-
       TER_NULL_ON_FAILURE is used, it returns FALSE if the variable is not set and NULL if the filter fails.

EXAMPLES
       Example #1

	      A filter_input(3) 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 $search_html.
";
	      echo "<a href='?search=$search_url'>Search again.</a>";
	      ?>

	      The above example will output something similar to:

	      You have searched for Me &#38; son.
	      <a href='?search=Me%20%26%20son'>Search again.</a>

SEE ALSO
       filter_var(3), filter_input_array(3), filter_var_array(3), "Types of filters".

PHP Documentation Group 													   FILTER_INPUT(3)