Are there any specific PHP functions or libraries recommended for filtering out unwanted characters or links in user-submitted data?

When dealing with user-submitted data, it's crucial to filter out unwanted characters or links to prevent security vulnerabilities such as cross-site scripting (XSS) attacks. One way to achieve this is by using PHP functions like `filter_var()` with the `FILTER_SANITIZE_STRING` filter to remove any potentially harmful characters. Additionally, you can utilize regular expressions to detect and remove URLs or links from the input data.

// Example code to filter out unwanted characters or links in user-submitted data
$userInput = $_POST['user_input'];

// Remove unwanted characters
$filteredInput = filter_var($userInput, FILTER_SANITIZE_STRING);

// Remove links using regular expressions
$filteredInput = preg_replace('/\b(?:https?|ftp):\/\/[^\s]+/i', '', $filteredInput);

// Use the filtered input in your application
echo $filteredInput;