css樣式：

.inner{
            width: 265px;
            height: 400px;
            position: absolute;
            top: 33px;
            left: 13px;
            /*cursor: pointer;*/
            overflow:hidden;
        }
        .innerbox{
            overflow-x: hidden;
            overflow-y: auto;
            color: #000;
            font-size: .7rem;
            font-family: "\5FAE\8F6F\96C5\9ED1",Helvetica,"黑體",Arial,Tahoma;
            height: 100%;
        }
        /*滾動條樣式*/
        .innerbox::-webkit-scrollbar {/*滾動條整體樣式*/
            width: 4px;     /*高寬分別對應橫豎滾動條的尺寸*/
            height: 4px;
        }
        .innerbox::-webkit-scrollbar-thumb {/*滾動條裡面小方塊*/
            border-radius: 5px;
            -webkit-box-shadow: inset 0 0 5px rgba(0,0,0,0.2);
            background: rgba(0,0,0,0.2);
        }
        .innerbox::-webkit-scrollbar-track {/*滾動條裡面軌道*/
            -webkit-box-shadow: inset 0 0 5px rgba(0,0,0,0.2);
            border-radius: 0;
            background: rgba(0,0,0,0.1);
        }
 

html程式碼：

<div class="inner">
    <div class="innerbox">
        <p style="height:200px;">這是內容111</p>
        <p style="height:400px;">這裡是內容222</p>
        <p>這裡是內容333</p>
    </div>
</div>