How to change offset on smooth scroll JQuery animation by a height of the navbar

Question

All my smooth scrolling works perfectly, however, the anchor stops at the very top of the page, but my navigation bar is fixed to the top, so what I need it to do, is offset the top by the height of the navbar. How would I go about this?

<script>
  $(document).ready(function(){
    // Add smooth scrolling to all links
    $("a").on('click', function(event) {

      // Make sure this.hash has a value before overriding default behavior
      if (this.hash !== "") {
        // Prevent default anchor click behavior
        event.preventDefault();

        // Store hash
        var hash = this.hash;

        // Using jQuery's animate() method to add smooth page scroll
        // The optional number (800) specifies the number of milliseconds
        // it takes to scroll to the specified area
        $('html, body').animate({
          scrollTop: $(hash).offset().top
        }, 1000, function(){

          // Add hash (#) to URL when done scrolling (default click behavior)
          window.location.hash = hash;
        });
      } // End if
    });
  });
</script>

Answer 1

非常简单： scrollTop: $('#hash').offset().top - navbarHeight 。