这是一个层拖动，网页上的拖拽Clone效果实例，两个层可在鼠标的拖动下，任意改变位置，智能判断层级，也就是智能判断自身是否处于最高层，最高处的层是不会被其它层遮挡的。
运行效果截图如下：
在线演示地址如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>拖拽--Clone</title> <style type="text/css"> body,div{margin:0;padding:0;} body{background:#3e3e3e;} div{position:absolute;width:100px;height:100px;cursor:move;border:1px solid #888;background:#000;} #drag1{top:100px;left:100px;} #drag2{top:100px;left:300px;} #temp{opacity:0.3;filter:alpha(opacity=30);} </style> <script type="text/javascript"> var zIndex = 1; window.onload = function () { var oDrag1 = document.getElementById("drag1"); var oDrag2 = document.getElementById("drag2"); drag(oDrag1); drag(oDrag2); }; function drag(oDrag) { var disX = dixY = 0; oDrag.onmousedown = function (event) { var event = event || window.event; disX = event.clientX - this.offsetLeft; disY = event.clientY - this.offsetTop; var oTemp = document.createElement("div"); oTemp["id"] = "temp"; oTemp.style.left = this.currentStyle ? this.currentStyle["left"] : getComputedStyle(this, null)["left"]; oTemp.style.top = this.currentStyle ? this.currentStyle["top"] : getComputedStyle(this, null)["top"]; oTemp.style.zIndex = zIndex++; document.body.appendChild(oTemp); document.onmousemove = function (event) { var event = event || window.event; var iL = event.clientX - disX; var iT = event.clientY - disY; var maxL = document.documentElement.clientWidth - oDrag.offsetWidth; var maxT = document.documentElement.clientHeight - oDrag.offsetHeight iL <= 0 && (iL = 0); iT <= 0 && (iT = 0); iL >= maxL && (iL = maxL); iT >= maxT && (iT = maxT); oTemp.style.left = iL + "px"; oTemp.style.top = iT + "px"; return false; }; document.onmouseup = function () { document.onmousemove = null; document.onmouseup = null; oDrag.style.left = oTemp.style.left; oDrag.style.top = oTemp.style.top; oDrag.style.zIndex = oTemp.style.zIndex; document.body.removeChild(oTemp); oDrag.releaseCapture && oDrag.releaseCapture() }; this.setCapture && this.setCapture(); return false } } </script> </head> <body> <div></div> <div></div> </body> </html>