function beginDrag(elementToDrag, event)
{
var x = parseInt(elementToDrag.style.left);
var y = parseInt(elementToDrag.style.top);

var deltaX = event.clientX - x;
var deltaY = event.clientY - y;

document.addEventListener("mousemove", moveHandler, true);
document.addEventListener("mouseup", upHandler, true);

event.stopPropagation();
event.preventDefault();

function moveHandler(event)
{
elementToDrag.style.left = (event.clientX - deltaX) + "px";
elementToDrag.style.top =  (event.clientY - deltaY) + "px";
event.stopPropagation();
}

function upHandler(event)
{
document.removeEventListener("mouseup", upHandler, true);
document.removeEventListener("mousemove", moveHandler, true);
event.stopPropagation();
}

}