JavaScript-实现滚动条

<!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>自制滚动条样式</title>
        <style type="text/css">
            #wraper{position:relative;width:500px;height:200px;padding-right:10px;background-color:#F6F6F6;overflow:hidden;}
            #slider{position:absolute;top:0;left:0;margin:0 10px;line-height:1.5;font-size:12px;color:#333;}
            #pannel{position:absolute;right:0;top:0;width:6px;height:100%;background-color:#EDEDEB;}
            #drag{position:absolute;left:0;width:6px;height:80px;background-color:#BCBCBA;cursor:pointer;}
        </style>
    </head>
    <body>    
        <div id="wraper">
            <div id="slider">
                <p>天翼手机俱乐部#今天下午,中国电信将联合摩托罗拉推出电信定制版的“刀锋战士”:锋云XT928。搭载4.5 英寸720p分辨率(1280 x 720 像素)高清触控屏,1300 万像素摄像头,运行Android 2.3 系统,内置 1.2GHz 双核处理器,拥有 1GB RAM。支持CDMA2000 EVDO+GSM双网双待,以及WIFI/WAPI接入移动互联网</p>
                <p>【酒量最好的前三名星座】冠军(巨蟹座)、亚军(魔羯座)、季军(金牛座)【酒品最好的前三名星座】冠军(天秤座)、亚军(双鱼座)、季军(水瓶座)【酒量不好,有酒胆,会耍宝的前三名星座】冠军(双子座)、亚军(射手座)、季军(狮子座)。</p>
                <p>【安卓软件推荐】动态企鹅桌面时钟是一款以一只可爱小企鹅为题材的桌面时钟!需要你在主屏幕按menu菜单键添加插件显示使用。它表情可爱,动作多多,你亦可连按小工具,它就会转换表情动作,另外还可以和小企鹅互动,喂它喝饮料,吃东西,还可以和小企鹅玩石头剪子布。</p>  
            </div>
            <div id="pannel">
                <div id="drag"></div>
            </div>
        </div>
        <script type="text/javascript">
            function customBar(oSlider, oPanel, oTrigger){
                this.parent = oSlider.parentNode;
                this.slider = oSlider;
                this.panel = oPanel;
                this.trigger = oTrigger;
                this.parentHeight = this.parent.clientHeight;
                this.sliderHeight = this.slider.offsetHeight;
                this.panelHeight = this.panel.clientHeight;
                this.triggerHeight = this.trigger.offsetHeight;
                this.k = (this.sliderHeight - this.parentHeight)/(this.panelHeight - this.triggerHeight);
                this.dis = 0;
                this.flag = false;
                this.init();
            }

            var oSlider = document.getElementById('slider'),
            oPanel = document.getElementById('pannel'),
            oTrigger = document.getElementById('drag');
            
            customBar.prototype = {
                init: function(){
                    if(this.k <= 0){
                        this.panel.style.display = 'none';
                        return;
                    }
                    this.slider.style.top = '0px';
                    this.trigger.style.top = '0px';
                    this.bind();
                },
                bind: function(){
                    var that = this;
                    this.trigger.onmousedown = function(e){
                        that.down.call(that, e);
                    }
                    this.trigger.onmousemove = document.onmousemove = function(e){
                        that.move.call(that, e);
                    }
                    this.trigger.onmouseup = document.onmouseup = function(e){
                        that.up.call(that, e);
                    }
                },
                down: function(e){
                    var e = window.event || e;
                    y1 = e.y || e.pageY;
                    y2 = parseInt(this.trigger.style.top);
                    this.dis = (y1 - y2);
                    this.flag = true;
                    this.move(e);
                },
                move: function(e){
                    if(!this.flag) return;
                    var e = window.event || e;
                    y1 = e.y || e.pageY;
                    dis = Math.min(Math.max(y1 - this.dis, 0), (this.panelHeight - this.triggerHeight));
                    this.slider.style.top = -dis * this.k + 'px';
                    this.trigger.style.top = dis + 'px';
                },
                up: function(){
                    this.flag = false;
                },
                wheel: function(){
                }
            }
            var ss = new customBar(oSlider, oPanel, oTrigger);
        </script>
    </body>
</html>
原文地址:https://www.cnblogs.com/JohnABC/p/3429939.html