大家帮我修改一下这段拖动div的代码：

[allforly]

drag = 0
move = 0

function init() {
window.document.onmousemove = mouseMove
window.document.onmousedown = mouseDown
window.document.onmouseup = mouseUp
window.document.ondragstart = mouseStop
}

function mouseDown() {
if (drag) {
clickleft = window.event.x - parseInt(dragObj.style.left)
clicktop = window.event.y - parseInt(dragObj.style.top)
dragObj.style.zIndex += 1
move = 1
}
}

function mouseStop() {
window.event.returnValue = false
}

function mouseMove() {
if (move) {
dragObj.style.left = window.event.x - clickleft
dragObj.style.top = window.event.y - clicktop
}
}

function mouseUp() {
move = 0
}

用这个调用：
<div id="mo" onmouseout="drag=0" onmouseover="dragObj=mo; drag=1;">moveing</div>

情况是这样的：我拉滚动条的时候，当鼠标移回页面里，div也跟着移动，请问这问题怎么解决呢？我不想鼠标回到页面时，div跟着动。
谢谢！