g1smd - 6:07 pm on Dec 10, 2012 (gmt 0)
HTML is the code that the browser sees, and it marks up the content as headings, paragraphs, lists, tables, forms, images and links.
PHP is a scripting language that runs on the server and can output HTML pages. The two things are not at all the same.
If the URL ends .html that might give a clue the site runs on static flat files. If the URL ends .php that might give a clue the site runs on a PHP scrript.