Mousedown on body and drag the page up or down, like on a pdf

Question

How would I make it so I can mousedown on the body on my page, then drag the page up or down, like you can in a PDF?

Basically I want to be able to drag the whole page u

Answer 1

Variation of Francesco's answer that includes scrolling along the X-axis:

$(function ()
{

  var   gesturesX = 0
    ,   gesturesY = 0
    ,      startX = 0
    ,      startY = 0
    , isMouseDown = false

  $(document.body).mousemove(function (e)
  {

    gesturesX = parseInt(e.pageX, 10)

    gesturesY = parseInt(e.pageY, 10)

    if (isMouseDown)
    {

      window.scrollBy(startX - gesturesX, startY - gesturesY)

      return false

    }

  }
  )

  $(document.body).mousedown(function ()
  {

    startX = gesturesX

    startY = gesturesY

    isMouseDown = true

    return false

  }
  )

  $(document.body).mouseup(function ()
  {

    isMouseDown = false

    return false

  }
  )

}
)