So I have this Javascript so when the screen is a certain size a button appears and you can hit the button for the navbar. However, it won't work, I have put the code in the nav section and the body and both did not work. Here is the JS:

<script>
    var navbar = document.getElementById(".navbarNav");
      function hideShow() {
        if (navbar.style.display == "block") {
          navbar.style.display = "none";
        } else {
          navbar.style.display = "block";
        }
      }
</script>