/*  div 움직이기 */

var img_L = 0;

var img_T = 0;

var targetObj;

function getLeft(o){

     return parseInt(o.style.left.replace('px', ''));

}

function getTop(o){

     return parseInt(o.style.top.replace('px', ''));

}

//움직이기

function moveDrag(e){

     var e_obj = window.event? window.event : e;

     var dmvx = parseInt(e_obj.clientX + img_L);

     var dmvy = parseInt(e_obj.clientY + img_T);

     targetObj.style.left = dmvx +"px";

     targetObj.style.top = dmvy +"px";

     return false;

}

//드래그 시작

function startDrag(e, obj) {

targetObj = obj;

     var e_obj = window.event? window.event : e;

     img_L = getLeft(obj) - e_obj.clientX;

     img_T = getTop(obj) - e_obj.clientY;

     document.onmousemove = moveDrag;

     document.onmouseup = stopDrag;

     if(e_obj.preventDefault)e_obj.preventDefault(); 

}

//드래그 멈추기

function stopDrag(){

     document.onmousemove = null;

     document.onmouseup = null;

}

그대로 사용해주면 된다.

＊참고 : http://horangi.tistory.com/249