Can you provide examples of how to sanitize and validate user input from HTML forms in PHP?

When dealing with user input from HTML forms in PHP, it is important to sanitize and validate the data to prevent security vulnerabilities such as SQL injection or cross-site scripting attacks. To sanitize user input, you can use functions like htmlspecialchars() to convert special characters to HTML entities. To validate user input, you can use functions like filter_var() with the appropriate filter flags. 

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

// Validate user input
if (filter_var($sanitized_input, FILTER_VALIDATE_EMAIL)) {
    // Input is a valid email address
} else {
    // Input is not a valid email address
}

Keywords

Sanitize Validate User Input HTML Forms PHP

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