Simple Parallax Scrolling

index.html

<!--
========================== NOTE ==========================
  This is an old post. I've made a new and easier parallax scrolling effect with images as backgrounds.

  Check it here: https://codepen.io/nikkz/pen/qZJKqG
-->

<div class="first-wrap">
  <div class="first-div">
    <p class="new-update">
      Note: Click
      <a href="https://codepen.io/nikkz/pen/qZJKqG" target="_blank">here</a>
      to see newer and easier parallax effect
    </p>
    <div class="first-inner-div">
      <p>Start Scrolling</p>
      <a href="#anchor">
        <span class="glyphicon glyphicon-circle-arrow-down down-arrow"></span>
      </a>      
    </div>
  </div>
</div>

<div class="second-wrap">
  <div class="second-div" id="anchor">
    <p class="body-text">
      <span class="line-separator"></span> Sample parallax with different background images
      <span class="line-separator"></span>
    </p>
  </div>
  <div class="third-div">
  </div>
</div>

<div class="third-wrap">
  <div class="fourth-div">
    <p class="body-text">
      <span class="line-separator"></span> Sample parallax with different background images
      <span class="line-separator"></span>
    </p>
  </div>
  <div class="fifth-div">
  </div>
</div>

<a href="#" id="back-to-top" title="Back to top">&uarr;</a>

script.js

/*
  jQuery codes for smooth scrolling. The following code is from
  https://css-tricks.com/snippets/jquery/smooth-scrolling/
*/
$(function() {
  $('a[href*=#]:not([href=#])').click(function() {
    if (location.pathname.replace(/^\//, '') == this.pathname.replace(/^\//, '') && location.hostname == this.hostname) {
      var target = $(this.hash);
      target = target.length ? target : $('[name=' + this.hash.slice(1) + ']');
      if (target.length) {
        $('html,body').animate({
          scrollTop: target.offset().top
        }, 700);
        return false;
      }
    }
  });
});

/*
  Back to top scroll button. The following code is from
  http://jsfiddle.net/gilbitron/Lt2wH/
*/
if ($('#back-to-top').length) {
  var scrollTrigger = 100, // px
    backToTop = function() {
      var scrollTop = $(window).scrollTop();
      if (scrollTop > scrollTrigger) {
        $('#back-to-top').addClass('show');
      } else {
        $('#back-to-top').removeClass('show');
      }
    };
  backToTop();
  $(window).on('scroll', function() {
    backToTop();
  });
  $('#back-to-top').on('click', function(e) {
    e.preventDefault();
    $('html,body').animate({
      scrollTop: 0
    }, 700);
  });
}

scripts

<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>

simple-parallax-scrolling.markdown

Simple Parallax Scrolling

A simple parallax scrolling that changes the background image when scrolling.

A Pen by Nikko Aboy on CodePen.

License.

style.less

/* Hides the horizontal overflow */

body {
  overflow-x: hidden;
}
/* Resize in Mobile View */

@media (min-width: 0) and (max-width: 767px) {
  p, .body-text {
    font-size: 10px !important;
  }
  .down-arrow {
    font-size: 20px !important;
  }
}
/* Resize in Tablet View */

@media (min-width: 768px) and (max-width: 991px) {
  p, .body-text {
    font-size: 15px !important;
  }
  .down-arrow {
    font-size: 30px !important;
  }
}
/* Line Separators CSS */

.line-separator {
  display: block;
  width: 50%;
  height: 1px;
  text-align: center;
  margin: 20px auto;
  border-bottom: 1px solid grey;
}
/* First Wrap Background */

.first-wrap {
  height: 100%;
  width: 100vw;
  background: #ffffff url("https://images.unsplash.com/photo-1445251836269-d158eaa028a6?fit=crop&fm=jpg&h=950&q=80&w=1920") no-repeat fixed;
   background-size: cover;
   background-position: 50% 50%;
}
/* Second Wrap Background */

.second-wrap {
  height: 100%;
  width: 100vw;
  background: #ffffff url("https://images.unsplash.com/photo-1444090542259-0af8fa96557e?fit=crop&fm=jpg&h=950&q=80&w=1920") no-repeat fixed;
  background-size: cover;
  background-position: 50% 50%;
}
/* Third Wrap Background */

.third-wrap {
  height: 100%;
  width: 100vw;
  background: #ffffff url("https://images.unsplash.com/photo-1443827423664-eac70d49dd0d?fit=crop&fm=jpg&h=950&q=80&w=1920") no-repeat fixed;
  background-size: cover;
  background-position: 50% 50%;
}

.first-div {
  position: relative;
  height: 100vh;
  width: 100vw;
  background-color: transparent;
  .first-inner-div {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    color: #fff;
    font-size: 20px;
    .down-arrow {
      font-size: 40px;
      color: #fff;
    }
    p {
      padding: 20px;
      letter-spacing: 0.45em;
      text-transform: uppercase;
      background-color: rgba(0, 0, 0, 0.3);
    }
  }
}

.second-div {
  display: table;
  height: 50vh;
  width: 100vw;
  background-color: rgba(255, 255, 255, 0.3);
  p {
    display: table-cell;
    vertical-align: middle;
    text-align: center;
    font-size: 20px;
    letter-spacing: 0.45em;
    text-transform: uppercase;
  }
}

.third-div {
  display: table;
  height: 50vh;
  width: 100vw;
  background-color: transparent;
}

.fourth-div {
  display: table;
  height: 50vh;
  width: 100vw;
  background-color: rgba(0, 0, 0, 0.3);
  p {
    display: table-cell;
    vertical-align: middle;
    text-align: center;
    color: #fff;
    font-size: 20px;
    letter-spacing: 0.45em;
    text-transform: uppercase;
  }
}

.fifth-div {
  display: table;
  height: 50vh;
  width: 100vw;
  background-color: transparent;
}

#back-to-top {
  position: fixed;
  bottom: 40px;
  right: 40px;
  z-index: 9999;
  width: 32px;
  height: 32px;
  text-align: center;
  line-height: 30px;
  background-color: rgb(255, 255, 255);
  color: #000;
  cursor: pointer;
  border: 0;
  border-radius: 2px;
  text-decoration: none;
  transition: opacity 0.2s ease-out;
  opacity: 0;
}

#back-to-top:hover {
  background-color: rgba(255, 255, 255, 0.8);
  color: #000;
}

#back-to-top.show {
  opacity: 1;
}



/* NEW UPDATE */
.new-update {
  padding: 20px;
  text-align: center;
  
}

styles

<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css" rel="stylesheet" />