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<html xmlns="http://www.w3.org/1999/xhtml">  
<head>  
<title>Js控制div层拖动/拖放代码_www.jb200.com</title>  
</head>  
<body>  
<script>  
var isIE = (document.all) ? true : false;  
var $ = function (id) {  
 return "string" == typeof id ? document.getElementById(id) : id;  
};  
var Class = {  
 create: function() {  
  return function() { this.initialize.apply(this, arguments); }  
 }  
}  
var Extend = function(destination, source) {  
 for (var property in source) {  
  destination[property] = source[property];  
 }  
}  
var Bind = function(object, fun) {  
 return function() {  
  return fun.apply(object, arguments);  
 }  
}  
var BindAsEventListener = function(object, fun) {  
 return function(event) {  
  return fun.call(object, (event || window.event));  
 }  
}  
var CurrentStyle = function(element){  
 return element.currentStyle || document.defaultView.getComputedStyle(element, null);  
}  
function addEventHandler(oTarget, sEventType, fnHandler) {  
 if (oTarget.addEventListener) {  
  oTarget.addEventListener(sEventType, fnHandler, false);  
 } else if (oTarget.attachEvent) {  
  oTarget.attachEvent("on" + sEventType, fnHandler);  
 } else {  
  oTarget["on" + sEventType] = fnHandler;  
 }  
};  
function removeEventHandler(oTarget, sEventType, fnHandler) {  
    if (oTarget.removeEventListener) {  
        oTarget.removeEventListener(sEventType, fnHandler, false);  
    } else if (oTarget.detachEvent) {  
        oTarget.detachEvent("on" + sEventType, fnHandler);  
    } else {  
        oTarget["on" + sEventType] = null;  
    }  
};  // www.jb200.com
var Drag = Class.create();  
Drag.prototype = {  
  //拖放对象  
  initialize: function(drag, options) {  
 this.Drag = $(drag);//拖放对象  
 this._x = this._y = 0;//记录鼠标相对拖放对象的位置  
 this._marginLeft = this._marginTop = 0;//记录margin  
 //事件对象(用于绑定移除事件)  
 this._fM = BindAsEventListener(this, this.Move);  
 this._fS = Bind(this, this.Stop);  
 this.SetOptions(options);  
 this.Limit = !!this.options.Limit;  
 this.mxLeft = parseInt(this.options.mxLeft);  
 this.mxRight = parseInt(this.options.mxRight);  
 this.mxTop = parseInt(this.options.mxTop);  
 this.mxBottom = parseInt(this.options.mxBottom);  
 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 = $(this.options.Handle) || this.Drag;  
 this._mxContainer = $(this.options.mxContainer) || null;  
 this.Drag.style.position = "absolute";  
 //透明  
 if(isIE && !!this.options.Transparent){  
  //填充拖放对象  
  with(this._Handle.appendChild(document.createElement("div")).style){  
   width = height = "100%"; backgroundColor = "#fff"; filter = "alpha(opacity:0)"; fontSize = 0;  
  }  
 }  
 //修正范围  
 this.Repair();  
 addEventHandler(this._Handle, "mou
sedown", BindAsEventListener(this, this.Start));  
  },  
  //设置默认属性  
  SetOptions: function(options) {  
 this.options = {//默认值  
  Handle:   "",//设置触发对象(不设置则使用拖放对象)  
  Limit:   false,//是否设置范围限制(为true时下面参数有用,可以是负数)  
  mxLeft:   0,//左边限制  
  mxRight:  9999,//右边限制  
  mxTop:   0,//上边限制  
  mxBottom:  9999,//下边限制  
  mxContainer: "",//指定限制在容器内,也就是一定范围内拖动  
  LockX:   false,//是否锁定水平方向拖放  
  LockY:   false,//是否锁定垂直方向拖放  
  Lock:   false,//是否锁定  
  Transparent: false,//是否透明显示拖动层  
  onStart:  function(){},//开始移动时执行  
  onMove:   function(){},//移动时执行  
  onStop:   function(){}//结束移动时执行  
 };  
 Extend(this.options, options || {});  
  },  
  //开始准备拖动  
  Start: function(oEvent) {  
 if(this.Lock){ return; }  
 this.Repair();  
 //记录鼠标相对拖放对象的位置  
 this._x = oEvent.clientX - this.Drag.offsetLeft;  
 this._y = oEvent.clientY - this.Drag.offsetTop;  
 //记录margin  
 this._marginLeft = parseInt(CurrentStyle(this.Drag).marginLeft) || 0;  
 this._marginTop = parseInt(CurrentStyle(this.Drag).marginTop) || 0;  
 //mousemove时移动 mouseup时停止  
 addEventHandler(document, "mousemove", this._fM);  
 addEventHandler(document, "mouseup", this._fS);  
 if(isIE){  
  //焦点丢失  
  addEventHandler(this._Handle, "losecapture", this._fS);  
  //设置鼠标捕获  
  this._Handle.setCapture();  
 }else{  
  //焦点丢失  
  addEventHandler(window, "blur", this._fS);  
  //阻止默认动作  
  oEvent.preventDefault();  
 };  
 //附加程序  
 this.onStart();  
  },  
  //修正范围  
  Repair: function() {  
 if(this.Limit){  
  //修正错误范围参数  
  this.mxRight = Math.max(this.mxRight, this.mxLeft + this.Drag.offsetWidth);  
  this.mxBottom = Math.max(this.mxBottom, this.mxTop + this.Drag.offsetHeight);  
  //如果有容器必须设置position为relative或absolute来相对或绝对定位,并在获取offset之前设置  
  !this._mxContainer || CurrentStyle(this._mxContainer).position == "relative" || CurrentStyle(this._mxContainer).position == "absolute" || (this._mxContainer.style.position = "relative");  
 }  
  },  
  //拖动  
  Move: function(oEvent) {  
 //判断是否锁定  
 if(this.Lock){ this.Stop(); return; };  
 //清除选择  
 window.getSelection ? window.getSelection().removeAllRanges() : document.selection.empty();  
 //设置移动参数  
 var iLeft = oEvent.clientX - this._x, iTop = oEvent.clientY - this._y;  
 //设置范围限制  
 if(this.Limit){  
  //设置范围参数  
  var mxLeft = this.mxLeft, mxRight = this.mxRight, mxTop = this.mxTop, mxBottom = this.mxBottom;  
  //如果设置了容器,再修正范围参数  
  if(!!this._mxContainer){  
   mxLeft = Math.max(mxLeft, 0);  
   mxTop = Math.max(mxTop, 0);  
   mxRight = Math.min(mxRight, this._mxContainer.clientWidth);  
   mxBottom = Math.min(mxBottom, this._mxContainer.clientHeight);  
  };  
  //修正移动参数  
  iLeft = Math.max(Math.min(iLeft, mxRight - this.Drag.offsetWidth), mxLeft);  
  iTop = Math.max(Math.min(iTop, mxBottom - this.Drag.offsetHeight), mxTop);  
 }  
 //设置位置,并修正margin  
 if(!this.LockX){ this.Drag.style.left = iLeft - this._marginLeft + "px"; }  
 if(!this.LockY){ this.Drag.style.top = iTop - this._marginTop + "px"; }  
 //附加程序  
 this.onMove();  
  },  
  //停止拖动  
  Stop: function() {  
 //移除事件  
 removeEventHandler(document, "mousemove", this._fM);  
 removeEventHandler(document, "mouseup", this._fS);  
 if(isIE){  
  removeEventHandler(this._Handle, "losecapture", this._fS);  
  this._Handle.releaseCapture();  
 }else{  
  removeEventHandler(window, "blur", this._fS);  
 };  
 //附加程序  
 this.onStop();  
  }  
};  
</script>  
<style>  
#idContainer{ border:10px solid #990000; width:600px; height:300px;}  
#idDrag{ border:5px solid #C4E3FD; background:#C4E3FD; width:50px; height:50px; top:50px; left:50px;}  
#idHandle{cursor:move; height:25px; background:#0000FF; overflow:hidden;}  
</style>  
<div id="idContainer">  
<div id="idDrag"><div id="idHandle"></div></div>  
</div>  
<input id="idReset" type="button" value="复位" />  
<input id="idLock" type="button" value="锁定" />  
<input id="idLockX" type="button" value="锁定水平" />  
<input id="idLockY" type="button" value="锁定垂直" />  
<input id="idLimit" type="button" value="范围锁定" />  
<input id="idLimitOff" type="button" value="取消范围锁定" />  
<br />拖放状态:<span id="idShow">未开始</span>  
<script>  
var drag = new Drag("idDrag", { mxContainer: "idContainer", Handle: "idHandle", Limit: true,  
 onStart: function(){ $("idShow").innerHTML = "开始拖放"; },  
 onMove: function(){ $("idShow").innerHTML = "left:"+this.Drag.offsetLeft+";top:"+this.Drag.offsetTop; },  
 onStop: function(){ $("idShow").innerHTML = "结束拖放"; }  
});  
$("idReset").onclick = function(){  
 drag.Limit = true;  
 drag.mxLeft = drag.mxTop = 0;  
 drag.mxRight = drag.mxBottom = 9999;  
 drag.LockX = drag.LockY = drag.Lock = false;  
}  
$("idLock").onclick = function(){ drag.Lock = true; }  
$("idLockX").onclick = function(){ drag.LockX = true; }  
$("idLockY").onclick = function(){ drag.LockY = true; }  
$("idLimit").onclick = function(){  drag.mxRight = drag.mxBottom = 200;drag.Limit = true; }  
$("idLimitOff").onclick = function(){ drag.Limit = false; }  
</script>  
</body>  
</html>