Javascript spacebar scroll to next anchor on page

Question

I have a single page website with multiple anchors. I am referencing this fiddle example for advancing the page to the next anchor when the mouse scrollwheel is used. Is there any way for me to modify this to also account for spacebar scrolling?

(function() {
  var delay = false;

  $(document).on('mousewheel DOMMouseScroll', function(event) {
    event.preventDefault();
    if(delay) return;

    delay = true;
    setTimeout(function(){delay = false},200)

    var wd = event.originalEvent.wheelDelta || -event.originalEvent.detail;

    var a= document.getElementsByTagName('a');
    if(wd < 0) {
      for(var i = 0 ; i < a.length ; i++) {
        var t = a[i].getClientRects()[0].top;
        if(t >= 40) break;
      }
    }
    else {
      for(var i = a.length-1 ; i >= 0 ; i--) {
        var t = a[i].getClientRects()[0].top;
        if(t < -20) break;
      }
    }
    $('html,body').animate({
      scrollTop: a[i].offsetTop
    });
  });
})();

Answer 1

http://jsfiddle.net/kamikazefish/t6LLybx8/201/

(function() {
  var delay = false;

  $(document).on('mousewheel DOMMouseScroll', function(event) {
    event.preventDefault();
    if(delay) return;

    delay = true;
    setTimeout(function(){delay = false},200)

    var wd = event.originalEvent.wheelDelta || -event.originalEvent.detail;

    var links = document.getElementsByTagName('a');
    var link;
    if(wd < 0) {
        link = findNext(links);
    }
    else {
        link = findPrevious(links);
    }

    animate(link);
  });

    $('body').keydown(function(e){
       if(e.keyCode == 8){
           e.preventDefault();
           // user has pressed backspace
           var links = document.getElementsByTagName('a');
           link = findPrevious(links);
           animate(link);
       }
       if(e.keyCode == 32){
           e.preventDefault();
           // user has pressed space
           var links = document.getElementsByTagName('a');
           link = findNext(links);
           animate(link);
       }
    });

  function findNext(links) {
       for(var i = 0 ; i < links.length ; i++) {
        var t = links[i].getClientRects()[0].top;
        if(t >= 40) return links[i];
      }
  }

  function findPrevious(links) {
      for(var i = links.length-1 ; i >= 0 ; i--) {
        var t = links[i].getClientRects()[0].top;
        if(t < -20) return links[i];
      }
  }

  function animate(link) {
    if( link ) {
      $('html,body').animate({
        scrollTop: link.offsetTop
      });
    }
  }
})();