一个超简单的JS拖拽实现代码(兼容IE,Firefox)

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" 
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml"> 
<head> 
<title>runcode</title> 
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" /> 
<meta name="Author" content="Sheneyan" /> 
<script type="text/javascript"> 
/** 
*取得元素的真实css属性 
*@param {Object} d 元素 
*@param {String} a 元素的css属性名 
*@version 0.2 
*/ 
function gs(d,a){ 
if (d.currentStyle){ 
var curVal=d.currentStyle[a] 
}else{ 
var curVal=document.defaultView.getComputedStyle(d, null)[a] 
} 
return curVal; 
} 
/** 
* 取得鼠标坐标 
* @return Position 
*/ 
function getMouseLocation(e){ 
if(!document.all){ 
mouseX = e.pageX; 
mouseY = e.pageY; 
} 
else{ 
mouseX = event.x + document.body.scrollLeft; 
mouseY = event.y + document.body.scrollTop; 
} 
return {x:mouseX,y:mouseY}; 
} 
/** 
* 拖动对象 
* @param {DOM Object} DOM对象 
*/ 
function drag(e,obj){ 
var p1 = getMouseLocation(e); 
var startRight = null; 
var startTop = null; 
var startLeft = null; 
var startBottom = null; 
var l = gs(obj,"left"); 
var r = gs(obj,"right"); 
var t = gs(obj,"top"); 
var b = gs(obj,"bottom"); 
if(!l) 
startRight = parseInt(r); 
else 
startLeft = parseInt(l); 
if(!t) 
startBottom = parseInt(b); 
else 
startTop = parseInt(t); 
if(obj.setCapture) 
obj.setCapture(); 
else if (window.captureEvents) 
window.captureEvents(Event.MOUSEMOVE|Event.MOUSEUP); 
document.onmousemove = function(e){ 
var p2 = getMouseLocation(e); 
var xMove = p2.x-p1.x; 
var yMove = p2.y-p1.y; 
if(!l) 
obj.style.right = (startRight - xMove)+"px"; 
else 
obj.style.left = (startLeft + xMove)+"px"; 
if(!t) 
obj.style.bottom = (startBottom - yMove)+"px"; 
else 
obj.style.top = (startTop + yMove)+"px"; 
} 
document.onmouseup = function(){ 
if(obj.releaseCapture) 
obj.releaseCapture(); 
else if (window.captureEvents) 
window.captureEvents(Event.MOUSEMOVE|Event.MOUSEUP); 
document.onmouseup = null; 
document.onmousemove = null; 
} 
} 
</script> 
<style type="text/css"> 
div#test{border:solid 1px blue;background:red;position:absolute;left:100px;top:200px;width:200px;height:200px;cursor:pointer;} 
</style> 
</head> 
<body> 
拖我拖我拖我拖我拖我拖我拖我 
</body> 
</html>

[Ctrl+A 全选注:如需引入外部Js需刷新才能执行]
javascript支持firefox,ie7页面布局拖拽效果代码