How to scroll through a div by dragging and not by using the scroll bars

Question

I am working on a project that uses a touch-screen interface. I have a div inside of a smaller div, so the smaller div has scroll bars to access the rest of the first div. Here

Answer 1

This works...I'd started making it for mobile safari before you cited FireFox...so it may have a little extra...

var _startX = 0;
var _startY = 0;
var _offsetX = 0;			
var _offsetY = 0;
var _dragElement;
document.onmousedown = OnMouseDown;
document.onmouseup = OnMouseUp;

function OnMouseDown(event){
  document.onmousemove = OnMouseMove;
    _startX = event.clientX;
  _startY = event.clientY;
  _offsetX = document.getElementById('div1').offsetLeft;
  _offsetY = document.getElementById('div1').offsetTop;
  _dragElement = document.getElementById('div1');

}

function OnMouseMove(event){
    _dragElement.style.left = (_offsetX + event.clientX - _startX) + 'px';
  _dragElement.style.top = (_offsetY + event.clientY - _startY) + 'px';
}

function OnMouseUp(event){
  document.onmousemove = null;
  _dragElement=null;
}

.div1{position:absolute; height:500px; width: 500px; z-index:1; background-color:red;}
.div2{position:absolute; top:100px; left:100px; height:100px; width:100px; z-index:2; overflow:hidden; display:block;}