Basic PHP Syntax
A PHP script can be placed anywhere in the document.
A PHP script starts with
<?php and ends with ?> :
The default file extension for PHP files is ".php".
A PHP file normally contains HTML tags, and some PHP scripting code.
Below, we have an example of a simple PHP file, with a PHP script that uses a built-in PHP function "echo" to output the text "Hello World!" on a web page:
<![CDATA[
<!DOCTYPE html>
<html>
<body>
<h1>My first PHP page</h1>
<?php echo "Hello World!"; ?>
</body>
</html>
]]>