What is phtml, and when should I use a .phtml extension rather than .php?

Question

I\'m wondering what the difference between .phtml and .php files is, and when to use one over the other.

Answer 1

To give an example to what Alex said, if you're using Magento, for example, .phtml files are only to be found in the /design area as template files, and contain both HTML and PHP lines. Meanwhile the PHP files are pure code and don't have any lines of HTML in them.