scrolling_dealie.html

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.5.1/jquery.min.js"></script>
<script type="text/javascript" charset="utf-8">
  jQuery.fn.exists = function() {
    return (this.length > 0)
  }

  jQuery.fn.doAwesomeScrollingThing = function() {
    return this.each(function() {
      $(this).click(function(event) {
        target = $('#' + this.href.split('#')[1])

        if (target.exists()) {
          event.preventDefault()
          var target_top = target.offset().top
          $('html, body').animate({ scrollTop: target_top - ($('.nav.flat').height() + 10) })
        }
      })
    })
  }

  jQuery.fn.isOmniPresentAllSeeingNav = function() {
    flatNav = this.first().clone().appendTo('body').addClass('flat').hide()
  }

  jQuery.fn.setCurrentSection = function() {
    if (this.is(':visible')) {
      this.find('a').each(function() {
        target = $('#' + this.href.split('#')[1])
        if ((target.offset().top + target.height()) > ($(window).scrollTop() + 50)) {
          $('.nav.flat a').removeClass('current')
          $(this).addClass('current')
          return false
        }
      })
    }
  }

  $(window).scroll(function() {
    menu = $('.nav.flat')

    if (($(window).scrollTop() > 500) && (!menu.is(':visible'))) {
      menu.fadeIn()
    }
    else if (($(window).scrollTop() < 500) && (menu.is(':visible'))) {
      menu.fadeOut()
    }
    menu.setCurrentSection()
  })

  $(document).ready(function() {
    $('body').css('margin-bottom', $(window).height())
    $('.nav').isOmniPresentAllSeeingNav()
    $('.scroll').doAwesomeScrollingThing()
  })
</script>

<style type="text/css" media="screen">
  body {
    margin: 0;
    padding: 0;
    font-size: 26px;
}
  .section {
    height: 500px;
    border-bottom: 1px solid green;
  }
  .nav {
    margin: 100px 0 500px;

  }
  .nav.flat {
    position: fixed;
    top: 0;
    left: 0;
    margin: 0;
    width: 100%;
    list-style: none;
    background-color: #ddd;
  }
  .nav.flat li { display: inline; }
  .nav.flat a {
    line-height: 2.1em;
    height: 51px;
    display: inline-block;
    margin: 0 11px;
  }
  .nav.flat a.current {
    background-color: red;
  }
</style>

<ul class="nav">
  <li><a class="scroll" href="#portfolio">Portfolio</a></li>
  <li><a class="scroll" href="#services">Services</a></li>
  <li><a class="scroll" href="#about">About</a></li>
  <li><a class="scroll" href="#contact">Contact</a></li>
</ul>

<div class="section" id="portfolio">
  <h1>Portfolio</h1>
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore
    et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut
    aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum
    dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui
    officia deserunt mollit anim id est laborum.</p>
</div>

<div class="section" id="services">
  <h1>Services</h1>
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore
    et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut
    aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum
    dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui
    officia deserunt mollit anim id est laborum.</p>
</div>

<div class="section" id="about">
  <h1>About</h1>
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore
    et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut
    aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum
    dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui
    officia deserunt mollit anim id est laborum.</p>
</div>

<div class="section" id="contact">
  <h1>Contact</h1>
  <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore
    et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut
    aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum
    dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui
    officia deserunt mollit anim id est laborum.</p>
</div>