How To Change Div To “Fixed” After Scroll

Question

At academicearth's about page, they have an <aside> tag on the right that is fixed once you start to scroll.

http://academicearth.org/about/

How is this done?

On top of the <aside> tag becoming fixed , it's also moved over just a bit to the right to fit the contents that appear from scrolling.

Answer 1

use scroll event..

$(document).scroll(function(e)
{ 
    //grab position of scrollbar
    position=$(document).scrollTop();
    //when position match a height
    if(position==desired_height)
    {
      //grab element 
      $('ele').css('position','fixed');
    }
}