<!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>拖拽庫(kù)</title>
<style type="text/css"> 
div,h2,p{margin:0;padding:0;}
body{font:14px/1.5 arial;}
#box{width:100px;height:100px;background:#fef4eb;padding:5px;margin:50px;border:1px solid #f60;}
#box .title{height:25px;background:#f60;}
#tool{margin-bottom:10px;}
</style>
<script type="text/javascript"> 
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");
  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()
 },
 //參數(shù)設(shè)置
 setOptions : function (options)
 {
  this.options =
  {
   handle:   this.drag, //事件對(duì)象
   limit:   true, //鎖定范圍
   lock:   false, //鎖定位置
   lockX:   false, //鎖定水平位置
   lockY:   false, //鎖定垂直位置
   maxContainer: document.documentElement || document.body, //指定限制容器
   onStart:  function () {}, //開(kāi)始時(shí)回調(diào)函數(shù)
   onMove:   function () {}, //拖拽時(shí)回調(diào)函數(shù)
   onStop:   function () {} //停止時(shí)回調(diào)函數(shù)
  };
  for (var p in options) this.options[p] = options[p]
 },
 //獲取id
 $ : function (id)
 {
  return typeof id === "string" ? document.getElementById(id) : id
 },
 //添加綁定事件
 addHandler : function (oElement, sEventType, fnHandler)
 {
  return oElement.addEventListener ? oElement.addEventListener(sEventType, fnHandler, false) : oElement.attachEvent("on" + sEventType, fnHandler)
 },
 //刪除綁定事件
 removeHandler : function (oElement, sEventType, fnHandler)
 {
  return oElement.removeEventListener ? oElement.removeEventListener(sEventType, fnHandler, false) : oElement.detachEvent("on" + sEventType, fnHandler)
 },
 //綁定事件到對(duì)象
 bind : function (object, fnHandler)
 {
  return function ()
  {
   return fnHandler.apply(object, arguments)
  }
 }
};
//應(yīng)用
window.onload = function ()
{
 var oBox = document.getElementById("box");
 var oTitle = oBox.getElementsByTagName("h2")[0];
 var oSpan = document.getElementsByTagName("span")[0];
 var oDrag = new Drag(oBox, {handle:oTitle, limit:false});
 var aInput = document.getElementsByTagName("input");
 //鎖定范圍接口
 aInput[0].onclick = function ()
 {
  oDrag.limit = !oDrag.limit;
  this.value = oDrag.limit ? "取消鎖定范圍" : "鎖定范圍"
 };
 
 //水平鎖定接口
 aInput[1].onclick = function ()
 {
  oDrag.lockX = !oDrag.lockX;
  this.value = oDrag.lockX ? "取消水平鎖定" : "水平鎖定"
 };
 
 //垂直鎖定接口
 aInput[2].onclick = function ()
 {
  oDrag.lockY = !oDrag.lockY;
  this.value = oDrag.lockY ? "取消垂直鎖定" : "垂直鎖定"
 };
 
 //鎖定位置接口
 aInput[3].onclick = function ()
 {
  oDrag.lock = !oDrag.lock;
  this.value = oDrag.lock ? "取消鎖定位置" : "鎖定位置"
 };
 
 //開(kāi)始拖拽時(shí)方法
 oDrag.onStart = function ()
 {
  oSpan.innerHTML = "開(kāi)始拖拽"
 };
 
 //開(kāi)始拖拽時(shí)方法
 oDrag.onMove = function ()
 {
  oSpan.innerHTML = "left:" + this.drag.offsetLeft + ", top:" + this.drag.offsetTop
 };
 //開(kāi)始拖拽時(shí)方法
 oDrag.onStop = function ()
 {
  oSpan.innerHTML = "結(jié)束拖拽"
 };
};
</script>
</head>
<body>
<div id="tool">
<input type="button" value="鎖定范圍" />
 <input type="button" value="水平鎖定" />
 <input type="button" value="垂直鎖定" />
 <input type="button" value="鎖定位置" />
</div>
<p>拖放狀態(tài)：<span>未開(kāi)始</span></p>
<div id="box">
 <h2 class="title"></h2>
</div>
</body>
</html>

希望本文所述對(duì)大家的JavaScript程序設(shè)計(jì)有所幫助。

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