JSFiddle - React, Tailwind, and code Playground

HTML

<li class="marcacao" onMouseOver="aumenta('html')">HTML5 e CSS3
    <div id="html" class="nivel">100</div>
</li>

<script>
    valorInicial = 0;
    function aumenta(id){
      setInterval(
        function(){
          var elemento = parseInt(document.getElementById(id).innerHTML);
          if(valorInicial <= 100)
            document.getElementById(id).innerHTML = valorInicial++;
    
        }
        ,20)
     }
</script>

CSS

.nivel{
    background-color: red;
    width: 100px;
}