How does parallax scrolling work? [closed]

Question

Was looking around some of these, and these, and these and more like this and finally this websites; and wondering how they work?

What front-end/back-end technologies make it possible?

How can I incorporate parallax scrolling in my project?

Answer 1

It's usually done via javascript and/or css. Do a View Source in Chrome on the sites you linked and you should be able to see the approaches they took to make it work.