Answer to Question #28653 in AJAX | JavaScript | HTML | PHP for Calvin

Question

Problem with HTML + PHP(print-on-screen commands), codes are appearing on screen rather then printed texts

<?php
echo "Hello World"."
"."Calvin";
?>

Result:
."
"."Calvin";

Method Tried:
Changing the codes, similar problem
Using other programming such as JavaScript and HTML, works

My assignment is to create a simple website for a business with online payment.