HTML5 is the latest and most enhanced version of HTML.Technically, HTML is not a programming language, but rather a markup language.
This tutorial gives very good understanding on HTML5.
Online HTML 5 Editor
You do not need to have your own environment to start learning C programming! We have set up an online compiler for you that can be used to compile and execute the programs online.
For most of the examples available in this tutorial, you will find a Try it option at the top right corner of the code box. Use it to verify the programs and check the outcome with different options. Feel free to modify any example and execute it online.
A HTML5 editor where you can type your HTML / XHTML code and see the result online.