Server-Side Validation

Removing White-Spaces trim()

$username = trim($_POST['username']);

• rtrim() Remove trailing spaces from a string
• ltrim() Remove leading spaces from a string

Special characters addslashes()

$username = addslashes($_POST['username');

• use stripslashes() to return the username to it’s previous format

Convert String into array

$usernames = explode(':', $colon_separated_names);

• use join() / implode() to convert array into string

String Length

$length = strlen($username);

String To UpperCase

	$strUpper = strtoupper($string);

• use strtolower() to convert string to LowerCase

ucfirst()

• Convert the first character of “hello” to uppercase

	echo ucfirst("hello world!");

ucwords()

• Convert the first character of each word to uppercase

	echo ucwords("hello world");

convert \n to <br/>

echo nl2br("List: \n 1- first options \n 2- second options");

• nl2br stands for New Line To <br>

Filter variable

// Input Sanitization To Avoid SQL Injection And XSS .....

$username = filter_var($_POST['username'], FILTER_SANITIZE_STRING);

$email = filter_var($_POST['email'], FILTER_SANITIZE_EMAIL);

$password = filter_var($_POST['password'], FILTER_SANITIZE_STRING);

$password = password_hash($password, PASSWORD_DEFAULT);