Here are the interview questions and answers for PHP Developer Jobs in the USA;

1. What is PHP?

   • PHP stands for Hypertext Preprocessor. It is a server-side scripting language used for web development.

2. Explain the difference between PHP and JavaScript.

   • PHP is a server-side language, while JavaScript is a client-side language. PHP is executed on the server, and the result is sent to the client, whereas JavaScript is executed on the client’s browser.

3. What are the advantages of using PHP?

   • PHP is open-source, platform-independent, and supports various databases. It is easy to learn, has a large community, and is well-suited for web development.

4. How do you comment in PHP?

   • Single-line comments start with //, and multi-line comments are enclosed between /* and */.

5. Explain the difference between include and require in PHP.

   • Both include and require are used to include files, but require will produce a fatal error if the file is not found, while include will only produce a warning.

6. What is the use of the “echo” statement in PHP?

   • The “echo” statement is used to output data to the screen. It can be used with or without parentheses.

7. Explain the difference between “echo” and “print” in PHP.

   • Both are used to output data, but “echo” can take multiple parameters, while “print” can only take one and always returns 1.

8. What is the purpose of the $_GET variable in PHP?

   • $_GET is used to collect form data after submitting an HTML form with the method=”get”.

9. What is the significance of the $_POST variable?

   • $_POST is used to collect form data after submitting an HTML form with the method=”post”.

10. How do you handle errors in PHP?

    • Errors can be handled using the “try”, “catch”, and “finally” blocks in PHP.

11. What is the use of the “session” in PHP?

    • Sessions are used to store user information on the server for later use.

12. Explain the difference between “unset” and “unlink” in PHP.

    • “unset” is used to destroy a variable, while “unlink” is used to delete a file.

13. What is the purpose of the “mysqli” extension in PHP?

    • “mysqli” is used for improved MySQL database connectivity, supporting features like prepared statements.

14. How can you prevent SQL injection in PHP?

    • Use prepared statements and parameterized queries to prevent SQL injection.

15. What is the use of the “header” function in PHP?

    • The “header” function is used to send raw HTTP headers to the browser.

16. Explain the difference between cookies and sessions.

    • Cookies are stored on the client side, while sessions are stored on the server side. Sessions are more secure.

17. How can you upload files in PHP?

    • File uploads are handled using the “move_uploaded_file” function.

18. What is the purpose of the “namespace” in PHP?

    • Namespaces are used to avoid naming conflicts and to encapsulate code.

19. Explain the use of the “foreach” loop in PHP.

    • The “foreach” loop is used to iterate over arrays and objects.

20. What is the ternary operator in PHP?

    • The ternary operator (?:) is a shorthand way of writing an if-else statement.

21. How can you connect to a database using PDO in PHP?

    • PDO (PHP Data Objects) is used for database connectivity. You can connect using the “new PDO” statement.

22. What is the purpose of the “trait” in PHP?

    • Traits are used to group functionality in a fine-grained and consistent way.

23. Explain the difference between “== and “===” in PHP.

    • “==” is the equality operator, while “===” is the identity operator. “===” checks both value and type.

24. How can you enable error reporting in PHP?

    • Error reporting can be enabled by adding “error_reporting(E_ALL);” at the beginning of your script.

25. What is the use of the “spl_autoload_register” function?

    • “spl_autoload_register” is used for automatic class loading, helping to avoid manual inclusion of class files.