What are the best practices for handling user input containing HTML or PHP code in PHP applications?

When handling user input containing HTML or PHP code in PHP applications, it is important to sanitize and validate the input to prevent security vulnerabilities such as Cross-Site Scripting (XSS) attacks. One way to do this is by using functions like htmlspecialchars() to encode special characters in the input. Additionally, you can use regular expressions or libraries like HTML Purifier to filter out potentially harmful code. 

// Example of sanitizing user input containing HTML or PHP code
$userInput = $_POST['user_input'];

// Sanitize the input using htmlspecialchars
$cleanInput = htmlspecialchars($userInput);

// Use the sanitized input in your application
echo "Cleaned user input: " . $cleanInput;

Keywords

htmlspecialchars htmlentities filter_var strip_tags cross-site scripting

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