弹出拖动层

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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
	<title></title>
	<meta http-equiv="Content-Type" content="text/html;charset=UTF-8" />
	<style type="text/css">
		*{margin:0;padding:0;}
		body{background:#fff;font-size:12px;}
		.drag_wrap{500px;height:300px;position:absolute;border:1px solid #ccc;display:none;z-index:3;background:#fff;}
		.drag_wrap h1{position:relative;height:35px;line-height:35px;text-indent:1em;font-size:14px;cursor:move;font-weight:normal;background:#efefef;border-bottom:1px solid #ccc;}
		.drag_wrap h1 span{position:absolute;font-size:12px;bottom:1px;right:10px;cursor:pointer;}
		.drag_cont{padding:10px;line-height:23px;text-indent:2em;}
		.mask{position:absolute;left:0;top:0;z-index:2;background:#000;filter:alpha(opacity=50);opacity: 0.5;}
		.in{margin:50px auto;80px;}
	</style>
</head>
<body>
	<div class="in"><input type="button" value="猛击我" onclick="drag.init().move('drag')" /></div>
	<div class="in"><a href="###" onclick="drag.init('drag2').move('drag2')">铁道部回应京沪高铁频出故障：设备处于磨合期</a></div>
	
	<div id="drag2" class="drag_wrap">
		<h1>铁道部回应京沪高铁频出故障<span>关闭</span></h1>
		<div class="drag_cont">
			<p>各位网友好！首先我要感谢人民网强国论坛为我提供与广大网友再聚的机会。在我来之前，看了许多网友的留言，其中就有一位网友提醒我要做好挨骂和挨拍的准备。是的，今天来到这里，就是代表铁路系统向大家真诚道歉、说明情况。京沪高铁开通半个月以来，总体客流和服务情况是好的。但近几天连续发生故障，影响列车正常运行</p>
			<p>6月30日，京沪高铁开通运营。请您介绍一下总体运营情况，比如开行列车数量、运送旅客人数、正点率、安全情况等。</p>
		</div>
	</div>
	
	<script type="text/javascript">
		var drag = {
			$: function(){ return document.getElementById(arguments[0]);},
			
			/**
			 * 得到视口的大小
			 */
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						pageWidth = de.clientWidth;
						pageHeight = de.clientHeight;
					} else { //如果是 Quirks mode
						pageWidth = document.body.clientWidth;
						pageHeight = document.body.clientHeight;
					}
				}
				return {
					 pageWidth,
					height: pageHeight
				}
			},
			
			/**
			 * 创建标签
			 * @param {String} target 标签名称，为空则创建一个空的div
			 * @param {Object} config 属性列表
			 */
			createElement: function(target, config){
				target = target || 'div';
				config = config || {};
				
				var tag = document.createElement(target);
				for(var p in config){
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						tag.style.cssText = config[p];
					} else if(p.toLowerCase() == 'class' || p.toLowerCase() == 'cls'){
						tag.className = config[p];
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						tag.innerHTML = config[p];
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						tag.setAttribute(p, config[p]);
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				}
				//此处try为释放tag引用，否则创建的DOM永远无法被释放
				try{
					return tag;
				} finally {
					tag = null;
				}
			},
			
			getEvent: function(event){
				return event ? event : window.event;
			},
			
			init: function(id){
				var that = this,
					ele = this.$(id) || false,
					winWidth = this.getWindowsSize().width,
					winHeight = this.getWindowsSize().height;
				
				if(!ele) {
					ele = this.createElement('div', {
						id: 'drag',
						cls: 'drag_wrap'
					});
					var h1 = this.createElement('h1');
					h1.innerHTML = '我是标题栏';
					var span = this.createElement('span');
					span.innerHTML = '关闭';
					var cont = this.createElement('div', {
						cls: 'drag_cont'
					});
					cont.innerHTML = '<p>上半年，面对复杂多变的国际形势和国内经济运行出现的新情况新问题，党中央、国务院坚持实施积极的财政政策和稳健的货币政策，不断加强和改善宏观调控，经济运行总体良好，继续朝着宏观调控预期方向发展。</p><p>初步测算，上半年国内生产总值204459亿元，按可比价格计算，同比增长9.6%；其中，一季度增长9.7%，二季度增长9.5%。分产业看，第一产业增加值15700亿元，增长3.2%；第二产业增加值102178亿元，增长11.0%；第三产业增加值86581亿元，增长9.2%。从环比看，二季度国内生产总值增长2.2%。</p>';
					
					h1.appendChild(span);
					ele.appendChild(h1);
					ele.appendChild(cont);
					//ele.style.display = 'block';
					
					document.body.appendChild(ele);
					
					span.onclick = function(){
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						document.body.removeChild(oMask);
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				} else {
					var handler = ele.getElementsByTagName('h1')[0],
						close = handler.getElementsByTagName('span')[0];
						
					close.onclick = function(){
						ele.style.display = 'none';
						document.body.removeChild(oMask);
					}
				}
				
				var oMask = this.createElement('div', {
					cls: 'mask'
				});
				oMask.style.cssText = '' + winWidth + 'px;height:' + winHeight + 'px;';
				
				document.body.appendChild(oMask);
				
				ele.style.display = 'block';
				ele.style.left = (winWidth - ele.offsetWidth)/2 + 'px';
				ele.style.top = (winHeight - ele.offsetHeight)/2 + 'px';
				
				return this;
			},
			
			move: function(id){
				var that = this,
					ele = this.$(id),
					winWidth = this.getWindowsSize().width,
					winHeight = this.getWindowsSize().height,
					posx,
					poy;
				
				if(!ele) return false;
				
				var handler = ele.getElementsByTagName('h1')[0],
					close = handler.getElementsByTagName('span')[0];
				handler.onmousedown = function(e){
					evt = that.getEvent(e);
					posx = evt.clientX - parseInt(ele.style.left);
					posy = evt.clientY - parseInt(ele.style.top);
					
					if (handler.setCapture) { //防止ie下拖动过快丢失对象
		                handler.setCapture();
		            } else if (window.captureEvents) {
		                window.captureEvents(e.MOUSEMOVE | e.MOUSEUP);
		            }
					
					document.onmousemove = function(e){
						e = that.getEvent(e);
						var l = e.clientX - posx,
							t = e.clientY - posy;
							
						if(l < 0){
							l = 0;
						} else if(l > winWidth - ele.offsetWidth){
							l = winWidth - ele.offsetWidth;
						}
						
						if(t < 0){
							t = 0;
						} else if(t > winHeight - ele.offsetHeight){
							t = winHeight - ele.offsetHeight;
						}
						
						ele.style.left = l + 'px';
						ele.style.top = t + 'px';
						
						window.getSelection ? window.getSelection().removeAllRanges() : document.selection.empty(); //取消选择文本
					}
					return false; //感谢清流鱼提出解决办法
				};
				
				document.onmouseup = function(e){
					e = that.getEvent(e);
					
					if (handler.releaseCapture) {
	                    handler.releaseCapture();
	                } else if (window.captureEvents) {
	                    window.captureEvents(e.MOUSEMOVE | e.MOUSEUP);
	                }
					
					document.onmousemove = null;
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				return this;
			},
			
			close: function(id){
				var that = this,
					ele = this.$(id);
					
				if(!ele) return false;
				ele.style.display = 'none';
			}
		}
		
	</script>
</body>
</html>

chorme下cursor:move样式丢失，感谢清流鱼提出解决办法，但还未搞清原理，记之。