Javascript 拖放div元素无法正常工作

我创建了一个简单的代码来拖放div元素，但效果不好。
当您将div元素快速拖动到任何方向

top

，

left

，

right

，

down

，鼠标光标将离开div元素，尽管我仍在按按钮

HTML

<div id="box"></div>

JavaScript

var elem = document.getElementById('box');
var PositionX = 0;
var PositionY = 0;
var MouseX = 0
var MouseY = 0;
var mouseDown = false;

elem.onmousedown = function(e) {
    PositionX = elem.offsetLeft;
    PositionY = elem.offsetTop;
    MouseX = e.clientX;
    MouseY = e.clientY;
    mouseDown = true;
};

elem.onmousemove = function(e) {
    if (mouseDown) {
    elem.style.left = PositionX + e.clientX - MouseX + "px";
    elem.style.top = PositionY + e.clientY - MouseY + "px";
  }
};

elem.onmouseover = function(e) {
    elem.style.cursor = 'move';
};

elem.onmouseup = function(e) {
    mouseDown = false;
};

---

尝试更改这一行：

elem.onmousemove = function(e) {

致：

---

尝试以下方法，希望它能完成您的工作：

var elem= document.getElementbyId('<%=box.ClientID%>');
elem.onmousemove= function(e) {
    if (mouseDown) {
    elem.style.left = PositionX + e.clientX - MouseX + "px";
    elem.style.top = PositionY + e.clientY - MouseY + "px";
  }
};

var elem=document.getElementbyId（“”）；
元素onmousemove=函数（e）{
如果（鼠标向下）{
elem.style.left=位置x+e.clientX-MouseX+“px”；
elem.style.top=PositionY+e.clientY-MouseY+px；
}
};

如果这对u不起作用，则u可以使用

document.onmousemove = function(e) {

var elem= document.getElementbyId('<%=box.ClientID%>');
elem.onmousemove= function(e) {
    if (mouseDown) {
    elem.style.left = PositionX + e.clientX - MouseX + "px";
    elem.style.top = PositionY + e.clientY - MouseY + "px";
  }
};