How we combine html,css,js,php?

Question

?

Answer 1

Most of the time, Php servers (interpreters) open indifferently '.php', '.htm' and '.html'... even so they sometimes differeciate version of Php by appending version number to the extention...

Anyway, if << you can mix up PHO inside HTML or vice versa >> as tell by @Adi Pratama-Universitas Brawijaya, you can only right open them with first a Php interpreter which will produce only Html code sended to client (user)... So, in a certain meaning, you can only embed Html in Php, because remaining Php code in Html opened in browser will be weirdly displayed...

Answer 2

Then what type of extension we have to save