title: how to implement scroll by drag using jquery
body: <p>Given a div with preset height (say 200px) set to hide overflowing content,
  and a child div with height of 600px,
  I want to be able to scroll the content div using a drag action.</p>
  
  <p>so that when a mouse down starts at some point and moves several pixels the content will scroll as well.</p>
  
  <p>optimally I would like to have some "speed and friction" logic added to this behavior so that you could "toss" the content div and have if continue its movement past the drop point.</p>
  
  <p>Does anyone know of such ready made functionality? in either JQuery / JQuery Ui or some plugin ?
  if not the implementation idea would also be welcome.</p>