What best practices should users follow when working with PHP forms and handling user input?

When working with PHP forms and handling user input, it is essential to sanitize and validate the input data to prevent security vulnerabilities such as SQL injection and cross-site scripting attacks. Users should always use functions like `htmlspecialchars()` and `mysqli_real_escape_string()` to sanitize input and validate data against expected formats using functions like `filter_var()`. 

// Sanitize user input using htmlspecialchars()
$clean_input = htmlspecialchars($_POST['user_input']);

// Validate user input using filter_var()
if(filter_var($_POST['email'], FILTER_VALIDATE_EMAIL)) {
    // Valid email address
} else {
    // Invalid email address
}

Keywords

validation sanitization XSS CSRF input filtering

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