JS实现的简易拖放效果示例

本文实例讲述了JS实现的简易拖放效果。分享给大家供大家参考，具体如下：

<!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=gb2312" />
<title>简易拖放效果</title>
</head>
<body>
<script type="text/JavaScript">
<!--
var isIE = (document.all) ? true : false;// 是否ie
var $ = function (id) {
  //返回id对象
  return "string" == typeof id ? document.getElementById(id) : id;
};
var Class = {
  // 带构造方法的类
  create: function() {
    return function() { this.initialize.apply(this, arguments); } //用apply应用下面的initialize初始化属性
  }
}
var Extend = function(destination, source) {
  //继承
  for (var property in source) {
    destination[property] = source[property];
  }
}
var Bind = function(object, fun) {
  return function() {
    return fun.apply(object, arguments);
  }
}
/**
用object对象调用fun参数是event||window event
**/
var BindAsEventListener = function(object, fun) {
  return function(event) {
    return fun.call(object, (event || window.event));
  }
}
/**
添加帧听器事件
@oTarget 目标对象
@sEventType 事件类型
@fnHandler 目标触发事件对象
**/
function addEventHandler(oTarget, sEventType, fnHandler) {
  if (oTarget.addEventListener) {
    oTarget.addEventListener(sEventType, fnHandler, false);//firefox
  } else if (oTarget.attachEvent) {
    oTarget.attachEvent("on" + sEventType, fnHandler);//ie
  } else {
    oTarget["on" + sEventType] = fnHandler;//other
  }
};
/**
清除添加的帧听器事件
@oTarget 目标对象
@sEventType 事件类型
@fnHandler 目标触发事件对象
**/
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;
  }
};
/*------------------------------相关模型构造完毕-----------------------------------*/
//拖放程序
var SimpleDrag = Class.create();
SimpleDrag.prototype = {
 //拖放对象,触发对象,初始化
 initialize: function(drag) {
  this.Drag = $(drag);
  this._x = this._y = 0;
  this._fM = BindAsEventListener(this, this.Move);//_fM方法就是应用MOVE方法参数是event||window.event
  this._fS = Bind(this, this.Stop);//_fS类方法就是Stop方法
  this.Drag.style.position = "absolute";
  this.Drag.style.cursor = "move";
  addEventHandler(this.Drag, "mousedown", BindAsEventListener(this, this.Start));
 },
 //准备拖动
 Start: function(oEvent) {
  this._x = oEvent.clientX - this.Drag.offsetLeft;
  this._y = oEvent.clientY - this.Drag.offsetTop;
  addEventHandler(document, "mousemove", this._fM);
  addEventHandler(document, "mouseup", this._fS);
 },
 //拖动
 Move: function(oEvent) {
  this.Drag.style.left = oEvent.clientX - this._x + "px";
  this.Drag.style.top = oEvent.clientY - this._y + "px";
 },
 //停止拖动
 Stop: function() {
  removeEventHandler(document, "mousemove", this._fM);
  removeEventHandler(document, "mouseup", this._fS);
 }
};
// -->
</script>
<div id="idDrag" style="border:5px solid #0000FF; background:#C4E3FD; width:50px; height:50px;"></div>
<script type="text/javascript">
<!--
new SimpleDrag("idDrag");
// -->
</script>
</body>
</html>

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希望本文所述对大家JavaScript程序设计有所帮助。

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