JavaScript拖拽 3.0

var drag = {
    enable : function(){
        var domIdStr = arguments[0];
        var parameter = {};
        if(arguments.length == 2){
            parameter = arguments[1];
        }
        var dom = document.getElementById(domIdStr);
        dom.innerHTML = '<div id="' + domIdStr + 'dragHead"><span id="' + domIdStr + 'dragTitle"></span><a id="' + domIdStr + 'closeDrag">关闭</a></div>' + dom.innerHTML;
        var title = document.getElementById(domIdStr + 'dragTitle');
        var close = document.getElementById(domIdStr + 'closeDrag');
        var head = document.getElementById(domIdStr + 'dragHead');
        var diffX = 0, diffY = 0, draging = false;
        dom.style.position = 'absolute';
        dom.style.zIndex = parameter.zIndex || '1000';
        dom.style.borderRadius = parameter.borderRadius || '4px';
        dom.style.visibility = 'visible';
        dom.style.width = parameter.width || '280px';
        dom.style.height = parameter.height || '230px';
        dom.style.backgroundColor = parameter.backgroundColor || '#F8F8F8';
        var left, top, cWidth, cHeight, dWidth = dom.offsetWidth, dHeight = dom.offsetHeight;
        if(document.compatMode == "BackCompat"){
            cWidth = document.body.clientWidth;
            cHeight = document.body.clientHeight;
        }else{
            cWidth = document.documentElement.clientWidth;
            cHeight = document.documentElement.clientHeight;
        }
        left = cWidth/2 - dWidth/2;
        top = cHeight/2 - dHeight/2;
        dom.style.left = parameter.left || left + 'px';
        dom.style.top = parameter.right || top + 'px';
        dom.style.border = '1px solid #CCC';
        head.style.cursor = 'move';
        head.style.margin = '0';
        head.style.backgroundColor = '#F2F2F2';
        head.style.borderBottom = '1px solid #CCC';
        head.style.padding = '5px';
        title.innerHTML = dom.title;
        close.style.cursor = 'pointer';
        close.style.cssFloat = 'right'; //Firefox
        close.style.styleFloat = 'right'; //IE
        
        head.onmousedown = function(e){
            e = e || window.event;
            draging = true;
			diffX = e.clientX - dom.offsetLeft;
			diffY = e.clientY - dom.offsetTop;
			if(head.setCapture){
			    head.setCapture();
			}
			head.onmousemove = function(e){
                e = e || window.event;
		        if(draging){
        	        dom.style.left = (e.clientX - diffX) + 'px';
        	        dom.style.top = (e.clientY - diffY) + 'px';
		        }
            };
	        head.onmouseup = function(e){
		        e = e || window.event;
		        if(head.releaseCapture){
		            head.releaseCapture();
		        }
		        draging = false;
		        head.onmousemove = null;
		        head.onmouseup = null;
	        };
        };
        
        close.onclick = function(){
            dom.style.visibility = 'hidden';
        };
    },
    disable: function(domIdStr){
        var dom = document.getElementById(domIdStr);
        dom.style.visibility = 'hidden';
    }
};

 用法：在HTML页面添加

<div id="drag" title="温馨提示"><div>此JavaScript拖拽版本号已飚到3.0</div></div>