PHP code island

In PHP, a code island (or code block) contains PHP code.

Description

All of your PHP code must be inside a code island. PHP code only functions as PHP code when it appears inside a code island.

PHP code islands must not include HTML, CSS or JavaScript; using these languages inside a code island will trigger a PHP error.

A PHP file commonly contains a mix of PHP code and HTML. The file might contain multiple code islands, divided by blocks of HTML.

Or, the PHP file might contain only PHP code, without any HTML.

A code island consists of a open marker and a close marker, like this:

<?php

?>

Or it could be expressed on a single line, like this:

<?php ?>

The example below shows a PHP code island inside a paragraph element:

<p>
<?php
  echo "Hello World";
?>
</p>

The above code sample is a mix of HTML (a paragraph tag), and a PHP code island (which will display "Hello World" for the user, inside the paragraph.

The echo keyword generates the text Hello World (the text inside the quotation marks -- not the quotes themselves).