分享一则JavaScript滚动条插件源码

                    //当前滚动条top位置
                    var currTop = (currScroll.endTop + position.y – currScroll.startTop);
                    //call是为了让this指针准确的指向本工作对象
                    currScroll.scrollEvent.call(currScroll, currTop);
                }
                return false;
            });
            //追加鼠标释放事件，为了准确的捕捉到释放事件在body上监听
            tool.addEvent(document.body, ‘mouseup’, function () {
                mouseUp.call(currScroll, []);
            });
            var mouseDown = function (e) {
                /// <summary>
                ///     1: 鼠标按下事件
                ///         1.1 – mouseDown(e) – 滚动条中鼠标按下滚动条事件
                /// </summary>
                /// <param name=”e” type=”Event”>
                ///     Event对象
                /// </param>
                /// <returns type=”linkFlyScroll” />
                currScroll.isDrag = true;
                //获取当前鼠标y位置
                currScroll.startTop = tool.getMousePos(e).y;