DOM-getElementsByClassName

<!DOCTYPE html>
<html>
<head>
    <title>Acessando class</title>
</head>
<body>
<div class="urso">ruuuu</div>
<div class="sherk">faz urruuu</div>
<script>
    console.log(
        document.getElementsByClassName("urso")[0]
    )
</script>
</body>
</html>