And, of course, that’s just the web page files. To extend the system usefulness into wider reaching applications, I’ve used server side scripts to write files that interact with separately running python and/or bash scripts. I haven’t yet written an application that uses the php to write a python script which is executed by a crontab command and writes a new php file and then a bash script and executes it to open a browser and send the new php file an HTTP request, which triggers it to write a…. and so on, but it’s not outside the realm of possibility.
I might make it sound a little ridiculous that there is such language diversity in these common and commonly interacting web development languages, but it does serve a purpose. It helps to separate the various subsystems involved in the process. If there was only one language involved, then there would have to be some extra syntax added to separate out the client side from the server, and the server and client from the databases. But that extra syntax wouldn’t be too hard to find an elegant solution for, especially with an object oriented language.