 
<!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=GBK" /> 
<title>拖拽</title> 
<script type="text/javascript" src="http://demo.jb51.net/jslib/jquery/jquery.js"></script> 
<style type="text/css"> 
*{margin: 0;padding: 0;} 
#drag{background: #ccc;height: 200px;width: 300px;text-align: center;line-height: 200px;position: absolute;left: 20px;top: 20px;} 
</style> 
<body> 
<div id="drag"> 
我可以拖動哦??！ 
</div> 
<script type="text/javascript"> 
//jquery方法拖拽 
/**$(function(){ 
var move = false; //判斷是否被移動 
var a = 0; 
var b = 0; 
$("#drag").mousedown(function(event){ 
move = true; 
a = event.pageX - parseInt($("#drag").css("left")); 
b = event.pageY - parseInt($("#drag").css("top")); 
}) 
$(document).mousemove(function(event){ 
if(move){ 
var x = event.pageX - a; 
var y = event.pageY - b; 
$("#drag").css({left: x,top: y}) 
} 
}).mouseup(function(){ 
move = false; 
}) 
})**/ 
//簡單的js一般方法 
/**var drag = document.getElementById("drag"); 
var a = 0; 
var b = 0; 
drag.onmousedown = function(event){ 
var event = event||window.event; 
a = event.clientX-drag.offsetLeft; 
b = event.clientY-drag.offsetTop; 
drag.onmousemove = function(event){ 
var event = event||window.event; 
var x = event.clientX - a; 
var y = event.clientY - b; 
drag.style.left = x + "px"; 
drag.style.top = y + "px"; 
} 
document.onmouseup=function(){ 
drag.onmousemove = null; 
drag.onmouseup = null; 
} 
}**/ 
//js面向對象方法 
function Drag(obj){ 
this.drag = document.getElementById(obj); 
//alert(obj); 
this.a = 0; 
this.b = 0; 
var that = this; 
this.drag.onmousedown = function(event){ 
that.mousedown(event); 
} 
} 
Drag.prototype.mousedown = function(event){ 
var event = event||window.event; 
this.a = event.clientX-this.drag.offsetLeft; 
this.b = event.clientY-this.drag.offsetTop; 
var that = this; 
document.onmousemove=function(event){ 
that.mousemove(event) 
} 
document.onmouseup=function(){ 
that.mouseup() 
} 
} 
Drag.prototype.mousemove = function(event){ 
var event = event||window.event; 
var x = event.clientX - this.a; 
var y = event.clientY - this.b; 
this.drag.style.left = x + "px"; 
this.drag.style.top = y + "px"; 
} 
Drag.prototype.mouseup=function(){ 
document.onmousemove = null; 
document.onmouseup = null; 
} 
new Drag("drag"); 
</script> 
</body> 
</html> 