JavaScript 拖放效果_html/css_WEB-ITnose

拖放效果，也叫拖拽、拖动。一个简单的拖放效果

拖动div

【程序说明】

首先初始化函数，对拖放对象添加mousedown监听事件

 initialize:function(drag){        this.Drag = $$(drag);//拖放对象        this._x = this._y = 0;//记录鼠标相对于拖放对象的位置        this._fM = BindAsEventListener(this, this.Move); //绑定拖动时执行的函数        this._fS = Bind(this, this.Stop); //绑定拖动结束执行的函数        this.Drag.style.position = "absolute";        EventUtil.addEventHandler(this.Drag, "mousedown", BindAsEventListener(this, this.Start));           //监听拖动对象mousedown事件 }

之后在Start方法添加mousemove和mouseup事件，分别监听拖放对象的位置和取消监听事件

             Start:function(oEvent){                 //记录mousedown触发时鼠标相对于拖放对象的位置                 this._x = oEvent.clientX - this.Drag.offsetLeft;                 this._y = oEvent.clientY - this.Drag.offsetTop;                 //监听mousemove 和 mouseup事件                 EventUtil.addEventHandler(document, "mousemove", this._fM);                 EventUtil.addEventHandler(document, "mouseup", this._fS);             }

完整拖放程序：

         /**          *拖放程序          */         var simpleDrag = Class.create();         simpleDrag.prototype = {             //初始化对象             initialize:function(drag){                 this.Drag = $$(drag);//拖放对象                 this._x = this._y = 0;//记录鼠标相对于拖放对象的位置                 this._fM = BindAsEventListener(this, this.Move); //绑定拖动时执行的函数                this._fS = Bind(this, this.Stop); //绑定拖动结束执行的函数                this.Drag.style.position = "absolute";                EventUtil.addEventHandler(this.Drag, "mousedown", BindAsEventListener(this, this.Start));                 //监听拖动对象mousedown事件             },             //准备拖动                 Start:function(oEvent){                 //记录mousedown触发时鼠标相对于拖放对象的位置                 this._x = oEvent.clientX - this.Drag.offsetLeft;                this._y = oEvent.clientY - this.Drag.offsetTop;                //监听mousemove 和 mouseup事件                EventUtil.addEventHandler(document, "mousemove", this._fM);                EventUtil.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(){                EventUtil.removeEventHandler(document, "mousemove", this._fM);                EventUtil.removeEventHandler(document, "mouseup", this._fS);             },         };        //初始化拖动         new simpleDrag('drag');

完整DEMO：

                         拖动div