说明：代码取自网络，注释为原文所有！
<!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <title>完美拖拽</title> <style type="text/css"> html, body { overflow: hidden; } body, div, h2, p { margin: 0; padding: 0; } body { color: #fff; background: #000; font: 12px/2 Arial; } p { padding: 0 10px; margin-top: 10px; } span {d color: #ff0; padding-left: 5px; } #box { position: absolute; width: 300px; height: 150px; background: #333; border: 2px solid #ccc; top: 50%; left: 50%; margin: -75px 0 0 -150px; } #box h2 { height: 25px; cursor: move; background: #222; border-bottom: 2px solid #ccc; text-align: right; padding: 0 10px; } #box h2 a { color: #fff; font: 12px/25px Arial; text-decoration: none; outline: none; } </style> <script type="text/javascript"> window.onload=function () { var oBox=document.getElementById("box"); var oH2 = oBox.getElementsByTagName("h2")[0]; var oA = oBox.getElementsByTagName("a")[0]; var aSpan = oBox.getElementsByTagName("span"); var disX = disY = 0; var bDrag = false; var aPos = [{x:oBox.offsetLeft, y:oBox.offsetTop}] //鼠标按下, 激活拖拽 oH2.onmousedown = function (event) { var event = event || window.event; bDrag = true; disX = event.clientX - oBox.offsetLeft; disY = event.clientY - oBox.offsetTop; aPos.push({x:oBox.offsetLeft, y:oBox.offsetTop}) this.setCapture && this.setCapture(); return false }; //拖拽开始 document.onmousemove = function (event) { if (!bDrag) return; var event = event || window.event; var iL = event.clientX - disX; var iT = event.clientY - disY; var maxL = document.documentElement.clientWidth - oBox.offsetWidth; var maxT = document.documentElement.clientHeight - oBox.offsetHeight; iL = iL < 0 ? 0 : iL; iL = iL > maxL ? maxL : iL; iT = iT < 0 ? 0 : iT; iT = iT > maxT ? maxT : iT; oBox.style.marginTop = oBox.style.marginLeft = 0; oBox.style.left = iL + "px"; oBox.style.top = iT + "px"; aPos.push({x:iL, y:iT}) status(); return false }; //鼠标释放, 结束拖拽 document.onmouseup = window.onblur = oH2.onlosecapture = function () { bDrag = false; oH2.releaseCapture && oH2.releaseCapture(); status() }; //回放拖动轨迹 oA.onclick = function () { if (aPos.length == 1) return; var timer = setInterval(function () { var oPos = aPos.pop(); oPos ? (oBox.style.left = oPos.x + "px", oBox.style.top = oPos.y + "px", status()) : clearInterval(timer) }, 30); this.focus = false;//去除链接虚线 return false }; //阻止冒泡 oA.onmousedown = function (event) { (event || window.event).cancelBubble = true }; //监听状态函数 function status () { aSpan[0].innerHTML = bDrag; aSpan[1].innerHTML = oBox.offsetTop; aSpan[2].innerHTML = oBox.offsetLeft } //初始调用 status() }; </script> </head> <body> <div id="box"> <h2><a href="javascript:;">点击回放拖动轨迹</a></h2> <p><strong>Drag:</strong><span></span></p> <p><strong>offsetTop:</strong><span></span></p> <p><strong>offsetLeft:</strong><span></span></p> </div> </body> </html>