gistfile1.js

// Smallest code to make a slider behavior by dragging the slider's handle
function sliderMousedown(event) {
  event.stop();
  mouseX = event.pointerX(), left = parseFloat(slider.style.marginLeft || 0);

  // Observe mousemove and mouseup on document for dragging behavior
  document.observe('mousemove', sliderMousemove).observe('mouseup', sliderMouseup);
}

function sliderMousemove(event) {
  // Compute slider relative position
  var dx   = event.pointerX() - mouseX, 
      pos  = (left + dx )/ width;
  carousel.goToRelative(pos, true);
  event.stop();
}

function sliderMouseup(event) {
  // Stop observing events on document
  document.stopObserving('mouseup', sliderMouseup).stopObserving('mousemove', sliderMousemove);
  event.stop();
}

slider.observe('mousedown', sliderMousedown);