What best practices should be followed when outputting data in HTML forms using PHP?

When outputting data in HTML forms using PHP, it is important to properly sanitize and escape the data to prevent any potential security vulnerabilities such as cross-site scripting (XSS) attacks. One common method to achieve this is by using the htmlspecialchars() function in PHP to convert special characters to HTML entities before outputting them in the form fields. 

<?php
// Example of outputting data in HTML form fields using PHP
$data = "<script>alert('XSS attack!');</script>";

// Sanitize and escape the data before outputting
$sanitized_data = htmlspecialchars($data, ENT_QUOTES, 'UTF-8');

// Output the sanitized data in the form field
echo "<input type='text' name='input_field' value='$sanitized_data'>";
?>

Keywords

htmlspecialchars htmlentities XSS form validation security

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