PHP Constants

A constant is case-sensitive by default.
By convention, constant identifiers are always uppercase.

Constants syntax

define(name, value, case-insensitive)
or
define(name, value)

Constants example

<html>
<body>
<?php
	define("C1", "PHP beginner course<br />", true);
	echo c1;

	define("C2", "PHP advanced course<br />", false);
	echo C2;

	define("C3", "PHP online<br />");
	echo C3;

	define("C4", "Learn PHP Constants");
	function functionTest() {
		echo C4;
	}
	functionTest();
?>
</body>
</html>

Result

PHP beginner course
PHP advanced course
PHP online
Learn PHP Constants