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PHP Filter

PHP filters are used to validate and sanitize user input, and is designed to make data validation easier and quicker.

Validating data = Determine if the data is in proper form.

Sanitizing data = Remove any illegal character from the data.

PHP filter_var() function

The filter_var() function both validate and sanitize data.

Example 1: Sanitize a String

   $str = "<h1>Hello World!</h1>";
   $newstr = filter_var($str, FILTER_SANITIZE_STRING);
   echo $newstr;

Example 2: Validate an Integer

$age = 30;
if (filter_var($age, FILTER_VALIDATE_INT)) {
	echo("Integer is valid");
} else {
	echo("Integer is not valid");

To validate 0 value use the following code:
if (filter_var($age, FILTER_VALIDATE_INT) === 0 || !filter_var($age, FILTER_VALIDATE_INT) === false)

Example 3: Validate integer value within a specified range.

$int = 50;
$min = 1;
$max = 100;

if (filter_var($int, FILTER_VALIDATE_INT, array("options" => array("min_range"=>$min, "max_range"=>$max))) === false) {
    echo("Value is not within the range");
} else {
    echo("Value is within the range");

Example 4: Sanitize and Validate an Email Address

$email = "";

// Remove all illegal characters from email
$email = filter_var($email, FILTER_SANITIZE_EMAIL);

// Validate e-mail
if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
    echo("$email is a valid email address");
} else {
    echo("$email is not a valid email address");

Example 5: Sanitize and Validate a URL

$url = "";

// Remove all illegal characters from a url
$url = filter_var($url, FILTER_SANITIZE_URL);

// Validate url
if (filter_var($url, FILTER_VALIDATE_URL)) {
    echo("$url is a valid URL");
} else {
    echo("$url is not a valid URL");



if(filter_var($var, FILTER_VALIDATE_BOOLEAN)){
    echo "Boolean Value is Valid";
    echo "Boolean Value is NOT Valid";
//Possible return values can be "1", "true", "on", "yes", "0", "false", "off" and "no"

Example 7: PHP Float Validate


if(filter_var($var, FILTER_VALIDATE_FLOAT)){
    echo "Float Value is Valid";
    echo "Float Value is NOT Valid";