<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8" />
	<title></title>
	<style type="text/css">
		div{ 
			position: absolute;
			width: 200px;
			height: 200px;
			background-color: #ccc;
		}
	</style></head>
<body style="position:relative;">
	<div style="top:50px;left:100px;">
		我是可以被拖拽的
	</div>	<div style="top:100px;left:300px;">
		我是可以被拖拽的
	</div>	<script type="text/javascript">
		var div = document.getElementsByTagName('div')[0];
		var mouseX = 0,mouseY=0;
		var divY =  0;//parseInt(div.style.top);		//当前元素 与窗口左上角 距离
		var divX =  0;//parseInt(div.style.left);		console.info(div.style.top,div.style.left);
		div.onmousedown =function(e){ 
			//鼠标按下:
			//1.获取当前元素的位置
			//2.获取鼠标的位置
		    divY =  parseInt(div.style.top);		//当前元素 与窗口左上角 距离
		    divX =  parseInt(div.style.left);
			e = e || event;
			mouseX = e.clientX;
			mouseY = e.clientY;			console.info(mouseX,mouseY);
			//记录当前鼠标的位置
			//div.onmousemove = function(e){ 
			document.onmousemove = function(e){ 
				e = e || event;				//获取鼠标的新位置
				var currentX = e.clientX;
				var currentY = e.clientY;				//计算元素的新位置
				var divNewX = divX - mouseX + currentX;
				var divNewY = divY - mouseY + currentY;
				div.style.top = divNewY + "px";
				div.style.left = divNewX + "px";				console.info("onmousemove",divNewX,divNewY);
			}
		}
		div.onmouseup =function(e){ 			//div.onmousemove = null;
			document.onmousemove = null;
			console.info("onmouseup")		}
	</script>
</body></html>