本代码实现的是，类似于点击登陆链接后,在窗口上弹出登陆对话框，并且使得对话框可以移动的方法
代码中有添加代码解释
本代码在chrome下通过测试
1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 2 <html xmlns="http://www.w3.org/1999/xhtml"> 3 <head> 4 <title></title> 5 <style> 6 .Middle{Position:absolute; 7 top:0; 8 left:0; 9 100%; 10 height:100%; 11 z-index:100; 12 background-color:RGBA(120,120,120,0.5); 13 } 14 .PopupBox{Position:absolute; 15 top:200px; 16 left:400px; 17 450px; 18 height:300px; 19 background-color:#999999; 20 z-index:102; 21 border-style:solid; 22 border-3px; 23 } 24 </style> 25 <script type="text/javascript"> 26 function Popup() { 27 var PBoxClick = 0; 28 var mid = document.createElement("div"); 29 mid.className = "Middle"; 30 document.body.appendChild(mid); 31 var PBox = document.createElement("div"); 32 PBox.className = "PopupBox"; 33 document.body.appendChild(PBox); 34 PBox.setAttribute("onmousedown", "MouseDown(this)"); 35 PBox.setAttribute("onmousemove","MouseMove(this)"); 36 PBox.setAttribute("onmouseup", "MouseUp(this)"); 37 PBox.setAttribute("moving", "0"); 38 PBox.style.cursor = "move"; 39 } 40 var movex = 0; //保存上次移动的鼠标X坐标 41 var movey = 0; //Y坐标 42 function MouseMove(n) { 43 44 if (n.moving == "down") { //如果鼠标down了，执行下面代码 45 if (movex != 0 && movey != 0) { //如果是第一次点击，表明movex和movey还没初始化，不执行下面代码 46 var x = parseInt(event.clientX - event.offsetX, 10) + (event.clientX - movex); 47 //可能是出于readonly的原因，div的坐标并不能通过n.style.left获取，所以采用了event.clientX - event.offsetX
//本人在这里纠结了很久，原来用n.style.left还以为是其他什么地方写错了
48 var y = parseInt(event.clientY - event.offsetY, 10) + (event.clientY-movey); 49 n.style.left = x + "px"; //设置div的位置 50 n.style.top = y + "px"; 51 } 52 movex = event.clientX;//保存这次鼠标坐标，供下次做移位使用 53 movey = event.clientY; 54 } 55 56 } 57 function MouseDown(n) { 58 n.moving = "down"; 59 } 60 function MouseUp(n) { 61 n.moving="up";
movex=0;
movey=0;} 62 63 </script> 64 </head> 65 <body> 66 <a href="javascript:Popup()">弹出窗口</a> 67 </body> 68 </html>