What are the potential security risks of allowing users to input HTML codes that can include scripts in PHP?

Allowing users to input HTML codes that can include scripts in PHP can lead to security risks such as cross-site scripting (XSS) attacks. To prevent this, it is essential to sanitize and validate user input before displaying it on the website. This can be done by using functions like htmlspecialchars() to escape special characters and prevent the execution of scripts embedded in the input. 

$user_input = "<script>alert('XSS attack!')</script>";
$sanitized_input = htmlspecialchars($user_input);
echo $sanitized_input;

Keywords

XSS Cross-site scripting Input validation htmlspecialchars htmlentities

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