drag.js

drag: function () {
            function startDrag(e) {
                // determine event object
                if (!e) {
                    var e = window.event;
                }
                if(e.preventDefault) e.preventDefault();

                // IE uses srcElement, others use target
                targ = e.target ? e.target : e.srcElement;

                if (targ.className != 'dragme') {return};
                // calculate event X, Y coordinates
                offsetX = e.clientX;
                offsetY = e.clientY;

                // assign default values for top and left properties
                if(!targ.style.left) { targ.style.left='0px'};
                if (!targ.style.top) { targ.style.top='0px'};

                // calculate integer values for top and left
                // properties
                coordX = parseInt(targ.style.left);
                coordY = parseInt(targ.style.top);
                drag = true;

                // move div element
                document.onmousemove=dragDiv;
                document.touchmove=dragDiv;
                return false;

            }
            function dragDiv(e) {
                if (!drag) {return};
                if (!e) { var e= window.event};
                // var targ=e.target?e.target:e.srcElement;
                // move div element
                targ.style.left=coordX+e.clientX-offsetX+'px';
                targ.style.top=coordY+e.clientY-offsetY+'px';
                return false;
            }
            function stopDrag() {
                drag=false;
            }

                document.onmousedown = startDrag;
                document.touchstart = startDrag;
                document.onmouseup = stopDrag;
                document.touchend = stopDrag;
        }