Computer Programming questions.?

[Majestad]

First of all, C++, Java, PHP and Python are programming languages but HTML is just a hypertext markup language. If you want to create programs you will need to know any of the first. If you want to start creating websites, I guess It would be good idea to learn HTML5, CSS, with those you are going to be able of creating the interface with a good style aside of that you wiill need to learn php, python or java, What for ? . Because with it you are going to put them to work, I mean registering users, showing information from the database, etc.

Facebook was done in php , mysql and It is implementing different types of technologies like ajax, and others.

If you want to start, I would recommend you to learn html,css, javascript and php, you can find courses on youtube.