If all you've worked on so far is HTML get ready to have your mind blown because web development is a very deep topic.
- HTML
- CSS
- Bootstrap
- JavaScript
- jQuery
- Node.js
- Express.js
- MongoDB
- Angular.js
You'll hear this stack of technologies referred to as the MEAN stack, and it includes all the major pieces you need to know to build complex web applications like Quora, Facebook or LinkedIn.
A good place to learn all this is Free Code Camp, and it wont cost you anything but time. About 1600 hours of time, but spread out over a year or so that becomes doable.
www.freecodecamp.com