From now on, we will work on your index.php file, so you can just start the web server, and go to http://localhost:8080 to see the results.

You might have already noticed that in order to write PHP code, you have to start the file with <?php. There are other options, and you can also finish the file with ?>, but none of them are needed. What is important to know is that you can mix PHP code with other content, like HTML, CSS, or JavaScript, in your PHP file as soon as you enclose the PHP bits with the <?php ?> tags.

<?php
  echo 'hello world';
?>
bye world

If you check the result of the preceding code snippet in your browser, you will see that it prints both messages, hello world and bye world. The reason why this happens is simple: you already know that the PHP code there prints the hello world message. What happens next is that anything outside the PHP tags will be interpreted as is. If there is an HTML code for instance, it would not be printed as is, but will...