PHP/HTML/HTML Cohabitation

Php and HTML Code Cohabitation

   <source lang="html4strict">

<?

echo "

Hello World! I"m using PHP!

";

?>

      </source>

   <source lang="html4strict">

<HTML> <HEAD> <?php

 $username = "User";

?> </HEAD> <BODY> <?php

 print("$username
");

?> </BODY> </HTML>

      </source>