title: Fix div from the bottom
body: <p>I want to create a section (like the right section on Facebook). A section fixed but from the bottom; as far as I scroll, the section scrolls. But when I reach the bottom of the section, it becomes fixed and stays on screen.</p>
  
  <p>I think it's not possible to do this with pure CSS, maybe JS..</p>
  
  <p>Do you have any solution for making this happen ?</p>
  
  <p>In advance, thanks.</p>