[рони]

как вариант ...

<meta charset="utf-8">
    <button id="back">&lt;</button>
    <span id="date"></span>
    <button id="forward">&gt;</button>
    <script>
        let curday = new Date();
        let date = curday.getDate();
        const sdate = document.getElementById('date');
        const opt = {
            weekday: 'long',
            year: 'numeric',
            month: 'long',
            day: 'numeric'
        };
        const intl = new Intl.DateTimeFormat('ru', opt);
        const outdate = (up = 0) => {
            curday.setDate(date + up);
            date = curday.getDate();
            sdate.textContent = intl.format(curday)
        }
        document.getElementById('back')
            .addEventListener('click', () => outdate(-1));
        document.getElementById('forward')
            .addEventListener('click', () => outdate(+1));
        outdate();
    </script>