What best practices should be followed when validating form input fields in PHP?

When validating form input fields in PHP, it is important to sanitize and validate user input to prevent security vulnerabilities such as SQL injection and cross-site scripting attacks. One common approach is to use PHP's filter_input function along with appropriate filter types to validate input data. Additionally, it is recommended to set up server-side validation rules to ensure that the data meets specific criteria before processing it further. 

// Example of validating a form input field in PHP
$input = filter_input(INPUT_POST, 'email', FILTER_VALIDATE_EMAIL);

if($input === false){
    // Invalid email format
    echo "Invalid email address";
} else {
    // Valid email format, proceed with processing the input
    echo "Email address is valid";
}

Keywords

filter_var htmlspecialchars validation sanitize input validation

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