XAMPP: can't get PHP to work

I saved a .php file to file:///C:/xampp/htdocs/tester/tester.php, and though my XHTML and CSS are working, my PHP is not. I put

<?php phpinfo(); ?>

as the first line of the body, and

<?php

echo "<p>Hello World</p>";

?>

a couple of paragraphs in. But when I view the page, nothing for phpinfo() shows up at all, and the Hello World bit shows up as:

Hello World"; ?>

Apache and MySQL are running. I've scoured the internet and can't find a solution, bu开发者_开发知识库t I feel like it's probably something very basic that I'm missing.

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Try to call your file with

localhost/tester/tester.php

instead of file:///C:/xampp/htdocs/tester/tester.php.