What are some common pitfalls when handling user input in PHP forms and how can they be avoided?

One common pitfall when handling user input in PHP forms is not properly sanitizing the data, leaving the application vulnerable to SQL injection attacks. This can be avoided by using prepared statements with parameterized queries to prevent malicious SQL code from being executed. 

// Example of using prepared statements to handle user input safely

// Establish a database connection
$pdo = new PDO('mysql:host=localhost;dbname=mydatabase', 'username', 'password');

// Prepare a SQL statement with a placeholder
$stmt = $pdo->prepare('SELECT * FROM users WHERE username = :username');

// Bind the user input to the placeholder
$stmt->bindParam(':username', $_POST['username']);

// Execute the query
$stmt->execute();

// Fetch the results
$results = $stmt->fetchAll();

Keywords

SQL injection Cross-site scripting Form validation Sanitization Input filtering

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