When I am starting to build a site that is going to require both HTML and PHP, should I be making a .html file with PHP in it (as in the file would be, say, index.html but within it there would be various tags)? Or, should I be making the files .php files and simply include HTML within it (as in the file would be, again say, index.php and it would start as PHP and I would simply intertwine HTML)?TL;DR: Should I be weaving HTML into .php files or weaving PHP into .html files?