What are some common beginner mistakes to avoid when working with PHP?

One common beginner mistake is not properly escaping user input, which can lead to security vulnerabilities such as SQL injection attacks. To avoid this, always use prepared statements or parameterized queries when interacting with databases to prevent malicious input from being executed as code. 

// Incorrect way without escaping input
$user_input = $_POST['username'];
$query = "SELECT * FROM users WHERE username = '$user_input'";
$result = mysqli_query($connection, $query);

// Correct way with prepared statement
$stmt = $connection->prepare("SELECT * FROM users WHERE username = ?");
$stmt->bind_param("s", $_POST['username']);
$stmt->execute();
$result = $stmt->get_result();

Keywords

syntax errors undefined variables SQL injection XSS vulnerabilities improper error handling

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