How can PHP developers ensure that their code outputs are interpreted correctly by browsers?

PHP developers can ensure that their code outputs are interpreted correctly by browsers by setting the correct content type header in their PHP scripts. This header tells the browser what type of content to expect from the server. By setting the content type to "text/html" or "application/json" depending on the output, developers can ensure that the browser interprets the response correctly.

<?php
header('Content-Type: text/html');
// PHP code here
?>