本文實例講述了JavaScript實現網頁對象拖放功能的方法。分享給大家供大家參考。具體如下：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><title>Drag</title><meta http-equiv="Content-Type" content="text/html;charset=utf-8"><style>#myDiv{width:50px; height:50px; background-color:red}</style></head><body><div id="myDiv"></div></body><script type="text/javascript"> var isIE = document.all ? true : false; //判斷是否是IE瀏覽器 function addEventHandler(oTarget, sEventType, fnHandler){ //添加事件 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) { //移除事件 if (oTarget.removeEventListener) { oTarget.removeEventListener(sEventType, fnHandler, false); } else if (oTarget.detachEvent) { oTarget.detachEvent("on" + sEventType, fnHandler); } else { oTarget["on" + sEventType] = null; } } var BindAsEventListener = function(object, fun) { //以另一個對象替換當前對象 return function(event) { return fun.call(object, (event || window.event)); } } var $ = function(id){ return document.getElementById(id); } var Class = { create: function() { return function() {this.initialize.apply(this, arguments);} } } var drag = Class.create(); drag.prototype = { initialize: function(id){//初始化 this._drag = $(id); this._flag = false; addEventHandler(this._drag,'mousedown',BindAsEventListener(this,this.start)); this._fM = BindAsEventListener(this, this.move); this._fS = BindAsEventListener(this, this.stop); this._drag.style.position = "absolute"; }, start: function(oEvent){//相當于onmousedown事件 //return this._name; this._x = oEvent.clientX - this._drag.offsetLeft; this._y = oEvent.clientY - this._drag.offsetTop; addEventHandler(document, 'mousemove', this._fM); addEventHandler(document, 'mouseup', this._fS); if(isIE){ addEventHandler(this._drag, "losecapture", this._fS); //焦點丟失 this._Handle.setCapture();//設置鼠標捕獲 }else{ addEventHandler(window, "blur", this._fS);//焦點丟失 oEvent.preventDefault();//阻止默認動作 } }, move: function(oEvent){ //相當于onmonusemove事件 this._drag.style.left = oEvent.clientX - this._x + "px"; this._drag.style.top = oEvent.clientY - this._y + "px"; }, stop: function(){ //相當于onmouseup事件 removeEventHandler(document, 'mousemove', this._fM); removeEventHandler(document, 'mouseup', this._fS); if(isIE){ removeEventHandler(this._drag, "losecapture", this._fS); this._Handle.releaseCapture(); }else{ removeEventHandler(window, "blur", this._fS); } } } var ndrag = new drag("myDiv");</script></html>希望本文所述對大家的javascript程序設計有所幫助。
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