Can the functions htmlspecialchars() and htmlentities() effectively prevent special characters from causing issues in PHP scripts?

Special characters can potentially cause security vulnerabilities or display issues in PHP scripts if not properly handled. The functions htmlspecialchars() and htmlentities() can help prevent these issues by converting special characters into their HTML entities, ensuring that they are safely displayed on the webpage without affecting the script execution.

// Using htmlspecialchars() to prevent special characters from causing issues
$unsafe_input = "<script>alert('XSS attack!')</script>";
$safe_input = htmlspecialchars($unsafe_input);
echo $safe_input;