I'm wonder how the custom scrollbar on Facebook has been made.
Is it only css or some javascript as well?
If yes can i have an idea of what the code looks like?
This question is specific to Facebook scrollbar style and not how to simply have a custom scrollbar
Facebook uses a very clever technique I described in context of my scrollbar plugin jsFancyScroll:
The scrolled content is actually scrolled natively by the browser scrolling mechanisms while the native scrollbar is hidden by using overflow definitions and the custom scrollbar is kept in sync by bi-directional event listening.
Feel free to use my plugin for your project: :)
https://github.com/leoselig/jsFancyScroll/
I highly recommend it over plugins such as TinyScrollbar that come with terrible performance issues!
If you're looking for a Facebook like scroll bar, then I'd highly recommend you take a look at this one:
http://rocha.la/jQuery-slimScroll
I solved this problem by adding another div as a sibling to the scrolling content div. It's height is set to the radius of the curved borders. There will be design issues if you have content that you want nudged to the very bottom, or text you want to flow into this new div, etc,. but for my UI this thin div is no problem.
The real trick is to have the following structure:
Important CSS highlights:
Here's what that looks like:
its a combination of both javascript and css
http://jscrollpane.kelvinluck.com/basic.html
This link should get you started. Long story short, a div that has been styled to look like a scrollbar is used to catch click-and-drag events. Wired up to these events are methods that scroll the contents of another div which is set to an arbitrary height and typically has a css rule of overflow:scroll (there are variants on the css rules but you get the idea).
I'm all about the learning experience -- but after you've learned how it works, I recommend using a library (of which there are many) to do it. It's one of those "don't reinvent" things...
EDIT If you want to skip the learning phase altogether, jassi9911 posted a link to a jQuery plugin that's dead-simple to use. Good stuff.