拖拽div 获取元素

//==== html ===============================

<div id="dv"></div>

//==== css ===============================

#dv {
100px;
height:100px;
background-color:blue;
border-radius:50%;
position:absolute;
}

//==== js ===============================

var dv = document.getElementById('zdy_time_id');
var x = 0;
var y = 0;
var l = 0;
var t = 0;
var isDown = false;
//鼠标按下事件
dv.onmousedown = function(e) {
//获取x坐标和y坐标
x = e.clientX;
y = e.clientY;

//获取左部和顶部的偏移量
l = dv.offsetLeft;
t = dv.offsetTop;
//开关打开
isDown = true;
//设置样式
dv.style.cursor = 'move';
}
//鼠标移动
window.onmousemove = function(e) {
if (isDown == false) {
return;
}
//获取x和y
var nx = e.clientX;
var ny = e.clientY;
//计算移动后的左偏移量和顶部的偏移量
var nl = nx - (x - l);
var nt = ny - (y - t);

dv.style.left = nl + 'px';
dv.style.top = nt + 'px';
}
//鼠标抬起事件
dv.onmouseup = function() {
//开关关闭
isDown = false;
dv.style.cursor = 'default';
}

https://www.jq22.com/webqd1348