效果:
HTML:
<!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=utf-8" />
<title>拖拽库靠谱</title>
<style type="text/css">
div,h2,p{margin:0;padding:0}
body{font:14px/1.5 arial}
#box{width:300px;height:100px;background:#fef4eb;padding:5px;border:1px solid #666}
#box #title{height:25px;background:#ccc;display:inline-block;cursor:move;width:100%;text-align:center}
.content{text-align:center;line-height:50px}
</style>
</head>
<body>
<div id="box">
<span id="title">按下拖拽</span>
<div class='content'>内容区</div>
</div>
<script src='drag.js'></script>
<script type="text/javascript">
//应用
var oBox = document.getElementById("box");
var oTitle = document.getElementById("title");
var oDrag = new Drag(oBox, {handle:oTitle, limit:false});
</script>
</body>
</html>
drag.js:
function Drag(){ //初始化 this.initialize.apply(this, arguments) } Drag.prototype = { //初始化 initialize : function (drag, options){ this.drag = this.$(drag); this._x = this._y = 0; this._moveDrag = this.bind(this, this.moveDrag); this._stopDrag = this.bind(this, this.stopDrag); this.setOptions(options); this.handle = this.$(this.options.handle); this.maxContainer = this.$(this.options.maxContainer); this.maxTop = Math.max(this.maxContainer.clientHeight, this.maxContainer.scrollHeight) - this.drag.offsetHeight; this.maxLeft = Math.max(this.maxContainer.clientWidth, this.maxContainer.scrollWidth) - this.drag.offsetWidth; this.limit = this.options.limit; this.lockX = this.options.lockX; this.lockY = this.options.lockY; this.lock = this.options.lock; this.onStart = this.options.onStart; this.onMove = this.options.onMove; this.onStop = this.options.onStop; this.handle.style.cursor = "move"; this.changeLayout(); this.addHandler(this.handle, "mousedown", this.bind(this, this.startDrag)) }, changeLayout : function (){ this.drag.style.top = this.drag.offsetTop + "px"; this.drag.style.left = this.drag.offsetLeft + "px"; this.drag.style.position = "absolute"; this.drag.style.margin = "0" }, startDrag : function (event){ var event = event || window.event; this._x = event.clientX - this.drag.offsetLeft; this._y = event.clientY - this.drag.offsetTop; this.addHandler(document, "mousemove", this._moveDrag); this.addHandler(document, "mouseup", this._stopDrag); event.preventDefault && event.preventDefault(); this.handle.setCapture && this.handle.setCapture(); this.onStart() }, moveDrag : function (event){ var event = event || window.event; var iTop = event.clientY - this._y; var iLeft = event.clientX - this._x; if (this.lock) return; this.limit && (iTop < 0 && (iTop = 0), iLeft < 0 && (iLeft = 0), iTop > this.maxTop && (iTop = this.maxTop), iLeft > this.maxLeft && (iLeft = this.maxLeft)); this.lockY || (this.drag.style.top = iTop + "px"); this.lockX || (this.drag.style.left = iLeft + "px"); var iWinWidth = document.documentElement.clientWidth; var iWinHeight = document.documentElement.clientHeight; if(this.drag.offsetLeft<0){ this.drag.style.left =0+'px'; }else if(this.drag.offsetLeft>(iWinWidth-this.drag.offsetWidth)){ this.drag.style.left =iWinWidth-this.drag.offsetWidth+'px'; } if(this.drag.offsetTop<0){ this.drag.style.top =0+'px'; }else if(this.drag.offsetTop>(iWinHeight-this.drag.offsetHeight)){ this.drag.style.top =iWinHeight-this.drag.offsetHeight+'px'; } event.preventDefault && event.preventDefault(); this.onMove() }, stopDrag : function (){ this.removeHandler(document, "mousemove", this._moveDrag); this.removeHandler(document, "mouseup", this._stopDrag); this.handle.releaseCapture && this.handle.releaseCapture(); this.onStop() }, //参数设置 setOptions : function (options){ this.options ={ handle: this.drag, //事件对象 limit: true, //锁定范围 lock: false, //锁定位置 lockX: false, //锁定水平位置 lockY: false, //锁定垂直位置 maxContainer: document.documentElement || document.body, //指定限制容器 onStart: function () {}, //开始时回调函数 onMove: function () {}, //拖拽时回调函数 onStop: function () {} //停止时回调函数 }; for (var p in options) this.options[p] = options[p] }, //获取id $ : function (id) { return typeof id === "string" ? document.getElementById(id) : id }, //添加绑定事件 addHandler : function (oElement, sEventType, fnHandler) { return oElement.addEventListener ? oElement.addEventListener(sEventType, fnHandler, false) : oElement.attachEvent("on" + sEventType, fnHandler) }, //删除绑定事件 removeHandler : function (oElement, sEventType, fnHandler) { return oElement.removeEventListener ? oElement.removeEventListener(sEventType, fnHandler, false) : oElement.detachEvent("on" + sEventType, fnHandler) }, //绑定事件到对象 bind : function (object, fnHandler) { return function () { return fnHandler.apply(object, arguments) } } };