jq如何实现内容的无限滚动

html:

<div>
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
        <li>4</li>
        <li>5</li>
        <li>1</li>
    </ul>
</div>

　　css:

      * {
            margin: 0;
            padding: 0;
        }

        div {
            width: 100px;
            height: 20px;
            overflow: hidden;
            border: 1px solid red;
            margin: 100px auto;
            position: relative;
        }

        li {
            height: 20px;
        }

        ul {
            position: absolute;
            left: 0;
            top: 0
        }

　　js:

    $(() => {
        let num = 0;
        setInterval(() => {
            num = $("ul").offset().top - 1;
            if (num === 1) {
                num = 101;
            }
            $("ul").offset({top: num});
        }, 20)
    })