JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container" id='block'></div>
<input type="button" id='prev' class='site_btn' width="50" value="prev">
<input type="button" id='next' class='site_btn' width="50" value="next">

<script type="text/javascript">
  let n = 0;
  const textArr = [
    'текст1',
    'текст2',
    'текст3',
    'текст4',
    'текст5'
  ];

  const divEl = document.querySelector('#block');
  divEl.innerHTML = textArr[n];

  document.querySelector('#next').addEventListener('click', () => {
    n = (n == textArr.length - 1) ? 0 : n + 1;
    divEl.innerHTML = textArr[n];
  });

  document.querySelector('#prev').addEventListener('click', () => {
    n = (n == 0) ? textArr.length - 1 : n - 1;
    divEl.innerHTML = textArr[n];
  });

</script>