What are some common pitfalls to avoid when handling quotation marks and escaping characters in PHP code?

One common pitfall to avoid when handling quotation marks and escaping characters in PHP code is forgetting to properly escape special characters within strings to prevent injection attacks or syntax errors. To solve this issue, use functions like addslashes() or mysqli_real_escape_string() to escape characters before including them in SQL queries or outputting them in HTML.

// Example of properly escaping characters in PHP code
$user_input = "John O'Connor";
$escaped_input = addslashes($user_input);

echo "Escaped input: " . $escaped_input;