<script type="text/javascript" src="//use.typekit.net/rws3een.js"></script>
<script type="text/javascript">try{Typekit.load();}catch(e){}</script>
<div class="container">
  <div class="container-inner">
    <div class="background"></div>
    <section id="intro" class="wrapper">
      <h1 class="name">Parallax Demo</h1>
      <h2 class="byline">An experiment by Dave Gamache</h2>
    </section>
    <section id="explosion" class="wrapper">
      <p class="explosion-byline">Here's an example of 16 elements scaling, fading and moving at once.</p>
      <ul id="domExplosionList">
        <li class="dom-explosion-item dei-1"></li>
        <li class="dom-explosion-item dei-2"></li>
        <li class="dom-explosion-item dei-3"></li>
        <li class="dom-explosion-item dei-4"></li>
        <li class="dom-explosion-item dei-5"></li>
        <li class="dom-explosion-item dei-6"></li>
        <li class="dom-explosion-item dei-7"></li>
        <li class="dom-explosion-item dei-8"></li>
        <li class="dom-explosion-item dei-9"></li>
        <li class="dom-explosion-item dei-10"></li>
        <li class="dom-explosion-item dei-11"></li>
        <li class="dom-explosion-item dei-12"></li>
        <li class="dom-explosion-item dei-13"></li>
        <li class="dom-explosion-item dei-14"></li>
        <li class="dom-explosion-item dei-15"></li>
        <li class="dom-explosion-item dei-16"></li>
      </ul>
    </section>
    <section id="images" class="wrapper">
      <p class="images-byline">Or better yet, a realistic example of showcasing some design work.</p>
      <p class="images-byline-2">Really, anything is possible &hellip;</p>
      <img id="mediumHomepage" class="raw-page" src="https://goo.gl/xRsl79">
      <div class="iphone">
        <img class="iphone-frame" src="https://goo.gl/1rjtLX">
        <div class="iphone-viewport">
          <img id="medium-profile-iphone" class="iphone-content" src="https://goo.gl/jFK9oy">
          <img id="davegamache-dot-com" class="iphone-content" src="https://goo.gl/nkqE1t">
        </div>
      </div>
    </section>
    <section id="links">
      <p class="links-byline">Learn how to make your parallax site smooth like this one.</p>
      <a class="btn" href="#">Read about it on Medium</a>
    </section>
  </div>
</div>
<h3 class="error">Whoops! Right now this demo doesn't handle resizing or browsers less than 1000px wide. Reload this page or get on a laptop!</h3>
/* #Reset & Basics (Inspired by E. Meyers)
================================================== */
	html, body, div, span, applet, object, iframe, h1, h2, h3, h4, h5, h6, p, blockquote, pre, a, abbr, acronym, address, big, cite, code, del, dfn, em, img, ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, b, u, i, center, dl, dt, dd, ol, ul, li, fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr, th, td, article, aside, canvas, details, embed, figure, figcaption, footer, header, hgroup, menu, nav, output, ruby, section, summary, time, mark, audio, video {
		margin: 0;
		padding: 0;
		border: 0;
		font-size: 100%;
		font: inherit;
		vertical-align: baseline; }
	article, aside, details, figcaption, figure, footer, header, hgroup, menu, nav, section {
		display: block; }
	body {		line-height: 1; }
	ol, ul {		list-style: none; }
	blockquote, q {		quotes: none; }
	blockquote:before, blockquote:after,
	q:before, q:after {
		content: '';
		content: none; }
	table {
		border-collapse: collapse;
		border-spacing: 0; }

/* #Basic Styles
================================================== */
	body {
		background: #fff;
		font: 24px/1.6 "brandon-grotesque", "HelveticaNeue", "Helvetica Neue", Helvetica, Arial, sans-serif;
		color: #fff;
		-webkit-font-smoothing: antialiased; /* Fix for webkit rendering */
		-webkit-text-size-adjust: 100%;
 }

/* #Typography
================================================== */
h1, h2, h3, h4, h5, h6 {	font-weight: bold;}
h1 { font-size: 60px; line-height: 1.1; }
h2 { font-size: 48px; line-height: 1.2; }
h3 { font-size: 36px; line-height: 1.3; }
h4 { font-size: 24px; line-height: 1.4; }
h5 { font-size: 21px; line-height: 1.5; }
h6 { font-size: 18px; line-height: 1.6; }
p { margin: 0 0 20px 0; }
em { font-style: italic; }
strong { font-weight: bold; }
hr { border: solid #ddd; border-width: 1px 0 0; clear: both; margin: 10px 0 30px; height: 0; }

/* #Links
================================================== */
	a { color: #333; text-decoration: underline; outline: 0; }
	a:hover, a:focus { color: #000; }
	p a, p a:visited { line-height: inherit; }
body {
  background: #111;
  font-weight: 300;
}
.background {
  position: fixed;
  width: 100%;
  height: 100%;
  background-image: url('https://goo.gl/LM6hUJ');
  background-size: cover;
  background-position: center;
  text-rendering: optimizeLegibility;
}
.background:after {
  content: '';
  position: fixed;
  top: 10px;
  right: 10px;
  bottom: 10px;
  left: 10px;
  border: 0;
}
.wrapper {
  display: none;
}


/* 1. Intro Keyframe
--------------------------------------- */
#intro {
  position: fixed;
  top: 48%;
  left: 10%;
  width: 80%;
  color: #fff;
  text-align: center;
  text-transform: uppercase;
}
.name {
  font-size: 35px;
  letter-spacing: 12px;
  line-height: 1.5;
  font-weight: 900;
}
.byline { 
  font-size: 15px;
  letter-spacing: 4px;
  text-align: center;
  font-weight: 300;
}
.ampersand {
  font-family: "Adobe Caslon Pro", "brandon-grotesque";
  font-style: italic;
}

/* 2. Explosion/Images/Links Structure and Text
--------------------------------------- */
#explosion,
#images {
  position: fixed;
  top: 100%;
  width: 100%;
  height: 100%;
}
.explosion-byline,
.images-byline {
  position: fixed;
  top: 63%;
  left: 10%;
  color: white;
  max-width: 22%;
  opacity: 0;
}
.images-byline-2 {
  text-align: center;
  position: fixed;
  top: 93%;
  left: 25%;
  color: white;
  width: 50%;
  opacity: 0;
}

/* 3. Explosion Keyframe
--------------------------------------- */
#domExplosionList {
  position: fixed;
  width: 270px;
  top: 100%;
  right: 15%;
  opacity: 0;
}
.dom-explosion-item {
  position: absolute;
  width: 60px;
  height: 60px;
  background-color: #fff;
}
.dei-1  { top: 0;   left: 0;  }
.dei-2  { top: 0;   left: 70px; }
.dei-3  { top: 0;   left: 140px; }
.dei-4  { top: 0;   left: 210px; }
.dei-5  { top: 70px;   left: 0;  }
.dei-6  { top: 70px;   left: 70px; }
.dei-7  { top: 70px;   left: 140px; }
.dei-8  { top: 70px;   left: 210px; }
.dei-9  { top: 140px;   left: 0;  }
.dei-10 { top: 140px;   left: 70px; }
.dei-11 { top: 140px;   left: 140px; }
.dei-12 { top: 140px;   left: 210px; }
.dei-13 { top: 210px;   left: 0;  }
.dei-14 { top: 210px;   left: 70px; }
.dei-15 { top: 210px;   left: 140px; }
.dei-16 { top: 210px;   left: 210px; }


/* 3. Images Keyframe
--------------------------------------- */
.raw-page {
  position: fixed;
  width: 45%;
  border-radius: 6px;
  box-shadow: inset 0 0 1px rgba(255,255,255,.3);
  border: 1px solid rgba(0,0,0,.2);
  background-clip: padding-box;
}
#mediumHomepage {
  top: 100%;
  right: 5%;
}
.iphone {
  position: fixed;
  right: 40%;
  top: 102%;
  width: 16%;
}
.iphone-frame {
  position: relative;
  width: 100%;
  height: auto;
  background-size: 100%;
  z-index: 2;
}
.iphone-viewport {
  width: 83.5%;
  height: 69.5%;
  position: absolute;
  top: 14%; 
  left: 8%;
  overflow: hidden;
  background-color: #000;
}
.iphone-content {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
}
#medium-profile-iphone {
  z-index: 2;
}

/* 3. Links Keyframe
--------------------------------------- */
#links {
  position: fixed;
  top: 48%;
  left: 10%;
  width: 80%;
  color: #fff;
  text-align: center;
  opacity: 0;
}
.links-byline {
  font-size: 30px;
  line-height: 1.15;
}
.btn {
  display: inline-block;
  padding: 10px 20px;
  border: 1px solid rgba(255,255,255,.5);
  color: rgba(255,255,255,.8);
  font-size: 12px;
  font-weight: 900;
  text-decoration: none;
  border-radius: 50px;
  text-align: center;
  text-transform: uppercase;
  letter-spacing: .1em;
}
.btn:hover,
.btn:focus {
  color: #fff;
  border-color: #fff;
}
.twitter {
  position: fixed;
  top: 20px;
  right: 20px;
}

/* 4. Handling resize and small devices
--------------------------------------- */
.error {
  display: none;
  position: fixed;
  width: 80%;
  font-size: 30px;
  font-weight: 300;
  text-align: center;
  top: 30%;
  left: 10%;
}
.page-error .error {
  *display: block;
}
.page-error .container {
  *display: none;
}
@media all and (max-width: 1000px) {
  .container {
    *display: none;
  }
  .error {
    *display: block;
    font-size: 22px;
  }
}
(function() {
  $(function() {

    /*  Globals
    -------------------------------------------------- */
    var PROPERTIES =               ['translateX', 'translateY', 'opacity', 'rotate', 'scale'],
        $window =                  $(window),
        $body =                    $('body'),
        wrappers =                 [],
        currentWrapper =           null,
        scrollTimeoutID =          0,
        bodyHeight =               0,
        windowHeight =             0,
        windowWidth =              0,
        prevKeyframesDurations =   0,
        scrollTop =                0,
        relativeScrollTop =        0,
        currentKeyframe =          0,
        keyframes = [
          {
            'wrapper' : '#intro',
            'duration' : '100%',
            'animations' :  [
              {
                'selector'    : '.name',
                'translateY'  : -140,
                'opacity'     : 0
              } , {
                'selector'    : '.byline',
                'translateY'  : -110,
                'opacity'     : 0
              } , {
                'selector'    : '.twitter',
                'opacity'     : [1, 0]
              }
            ]
          } , {
            'wrapper' : '#explosion',
            'duration' : '150%',
            'animations' :  [
              {
                'selector'    : '.explosion-byline',
                'translateY'  : '-25%',
                'opacity'     : [0, 1.75] // hack to accelrate opacity speed
              } , {
                'selector'    : '#domExplosionList',
                'translateY'  : '-70%',
                'opacity'     : [0, 1] // hack to accelrate opacity speed
              }
            ]
          } , {
            'wrapper' : '#explosion',
            'duration' : '150%',
            'animations' :  [
              {
                'selector'    : '.dei-1',
                'translateY'  : '-15%',
                'translateX'  : '-10%',
                'opacity'     : [1, 0],
                'scale'       : 2,
              } , {
                'selector'    : '.dei-2',
                'translateY'  : '-5%',
                'translateX'  : '-4%',
                'opacity'     : [1, 0] // hack to decelrate opacity speed
              } , {
                'selector'    : '.dei-3',
                'translateY'  : '-9%',
                'translateX'  : '2%',
                'opacity'     : [1, 0], // hack to accelrate opacity speed
                'scale'       : 1.2,
              } , {
                'selector'    : '.dei-4',
                'translateY'  : '-17%',
                'translateX'  : '8%',
                'opacity'     : [1, 0], // hack to accelrate opacity speed
                'scale'       : 1.5,
              } , {
                'selector'    : '.dei-5',
                'translateY'  : '-2%',
                'translateX'  : '-15%',
                'opacity'     : [1, 0],
                'scale'       : 2,
              } , {
                'selector'    : '.dei-6',
                'translateY'  : '-1%',
                'translateX'  : '-7%',
                'opacity'     : [1, 0], // hack to decelrate opacity speed
                'scale'       : 1.2,
              } , {
                'selector'    : '.dei-7',
                'translateY'  : '-4%',
                'translateX'  : '2%',
                'opacity'     : [1, 0], // hack to accelrate opacity speed
                'scale'       : 1.1,
              } , {
                'selector'    : '.dei-8',
                'translateY'  : '-3%',
                'translateX'  : '12%',
                'opacity'     : [1, 0], // hack to accelrate opacity speed
                'scale'       : 1.8,
              } , {
                'selector'    : '.dei-9',
                'translateY'  : '3%',
                'translateX'  : '-12%',
                'opacity'     : [1, 0],
                'scale'       : 1.5,
              } , {
                'selector'    : '.dei-10',
                'translateY'  : '5%',
                'translateX'  : '-4%',
                'opacity'     : [1, 0] // hack to decelrate opacity speed
              } , {
                'selector'    : '.dei-11',
                'translateY'  : '8%',
                'translateX'  : '6%',
                'opacity'     : [1, 0], // hack to accelrate opacity speed
                'scale'       : 1.4,
              } , {
                'selector'    : '.dei-12',
                'translateY'  : '1%',
                'translateX'  : '20%',
                'opacity'     : [1, 0], // hack to accelrate opacity speed
                'scale'       : 1.9,
              } , {
                'selector'    : '.dei-13',
                'translateY'  : '8%',
                'translateX'  : '-12%',
                'opacity'     : [1, 0],
                'scale'       : 1.8,
              } , {
                'selector'    : '.dei-14',
                'translateY'  : '4%',
                'translateX'  : '-3%',
                'opacity'     : [1, 0], // hack to decelrate opacity speed
                'scale'       : 1.3,
              } , {
                'selector'    : '.dei-15',
                'translateY'  : '14%',
                'translateX'  : '5%',
                'opacity'     : [1, 0], // hack to accelrate opacity speed
                'scale'       : 1.7,
              } , {
                'selector'    : '.dei-16',
                'translateY'  : '6%',
                'translateX'  : '9%',
                'opacity'     : [1, 0], // hack to accelrate opacity speed
                'scale'       : 2,
              }
            ]
          } , {
            'wrapper' : '#explosion',
            'duration' : '100%',
            'animations' :  [
              {
                'selector'    : '.explosion-byline',
                'translateY'  : ['-25%', '-40%'],
                'opacity'     : [1, 0] // hack to accelrate opacity speed
              }
            ]
          } , {
            'wrapper' : '#images',
            'duration' : '150%',
            'animations' :  [
              {
                'selector'    : '.images-byline',
                'translateY'  : '-25%',
                'opacity'     : [0, 1.75] // hack to accelrate opacity speed
              } , {
                'selector'    : '#mediumHomepage',
                'translateY'  : '-90%'
              } , {
                'selector'    : '.iphone',
                'translateY'  : '-66%'
              }
            ]
          } , {
            'wrapper' : '#images',
            'duration' : '75%',
            'animations' :  []
          } , {
            'wrapper' : '#images',
            'duration' : '150%',
            'animations' :  [
              {
                'selector'    : '.images-byline',
                'translateY'  : ['-25%', '-25%'],
                'scale'       : .7,
                'opacity'     : [1.75, -.75] // hack to accelrate opacity speed
              } , {
                'selector'    : '.images-byline-2',
                'opacity'     : [0, 1],
                'translateY'  : '-15%'
              } , {
                'selector'    : '#mediumHomepage',
                'translateY'  : ['-90%', '-90%'],
                'scale'       : .8,
                'opacity'     : -.75
              } , {
                'selector'    : '.iphone',
                'translateY'  : ['-66%', '-90%'],
                'translateX'  : '-2%',
                'rotate'      : -90,
                'scale'       : 1.3
              } , {
                'selector'    : '#medium-profile-iphone',
                'scale'       : .9,
                'translateX'  : '20%',
              } , {
                'selector'    : '#davegamache-dot-com',
                'scale'       : [.5, 1]
              }
            ]
          } , {
            'wrapper' : '#images',
            'duration' : '40%',
            'animations' :  []
          } , {
            'wrapper' : '#images',
            'duration' : '150%',
            'animations' :  [
              {
                'selector'    : '.images-byline-2',
                'opacity'     : [1, .5],
                'translateY'  : ['-15%', '50%'],
                'opacity'     : [1, -2]
              } , {
                'selector'    : '.iphone',
                'translateY'  : ['-90%', '5%'],
                'translateX'  : ['-2%', '-2%'],
                'rotate'      : [-90, -90],
                'scale'       : [1.3, 1.3]
              } , {
                'selector'    : '#medium-profile-iphone',
                'translateX'  : ['20%', '20%']
              } , {
                'selector'    : '#davegamache-dot-com',
                'scale'       : [1, 1]
              }
            ]
          } , {
            'wrapper' : '#links',
            'duration' : '100%',
            'animations' :  [
              {
                'selector'    : '#links',
                'opacity'     : [0, 2],
                'scale'       : [.8, 1]
              } , {
                'selector'    : '.twitter',
                'opacity'     : [0, 1]
              }
            ]
          } , {
            'duration' : '100%',
            'animations' :  []
          }
        ]

    /*  Construction
    -------------------------------------------------- */
    init = function() {
      scrollIntervalID = setInterval(updatePage, 10);
      setupValues();
      $window.resize(throwError)
      if(isTouchDevice) {
        $window.resize(throwError)
      }
    }

    setupValues = function() {
      scrollTop = $window.scrollTop();
      windowHeight = $window.height();
      windowWidth = $window.width();
      convertAllPropsToPx();
      buildPage();
    }

    buildPage = function() {
      var i, j, k;
      for(i=0;i<keyframes.length;i++) { // loop keyframes
          bodyHeight += keyframes[i].duration;
          if($.inArray(keyframes[i].wrapper, wrappers) == -1) {
            wrappers.push(keyframes[i].wrapper);
          }
          for(j=0;j<keyframes[i].animations.length;j++) { // loop animations
            Object.keys(keyframes[i].animations[j]).forEach(function(key) { // loop properties
              value = keyframes[i].animations[j][key];
              if(key !== 'selector' && value instanceof Array === false) {
                var valueSet = [];
                valueSet.push(getDefaultPropertyValue(key), value);
                value = valueSet;
              }
              keyframes[i].animations[j][key] = value;
            });
          }
      }
      $body.height(bodyHeight);
      $window.scroll(0);
      currentWrapper = wrappers[0];
      $(currentWrapper).show();
    }

    convertAllPropsToPx = function() {
      var i, j, k;
      for(i=0;i<keyframes.length;i++) { // loop keyframes
        keyframes[i].duration = convertPercentToPx(keyframes[i].duration, 'y');
        for(j=0;j<keyframes[i].animations.length;j++) { // loop animations
          Object.keys(keyframes[i].animations[j]).forEach(function(key) { // loop properties
            value = keyframes[i].animations[j][key];
            if(key !== 'selector') {
              if(value instanceof Array) { // if its an array
                for(k=0;k<value.length;k++) { // if value in array is %
                  if(typeof value[k] === "string") {
                    if(key === 'translateY') {
                      value[k] = convertPercentToPx(value[k], 'y');
                    } else {
                      value[k] = convertPercentToPx(value[k], 'x');
                    }
                  }
                } 
              } else {
                if(typeof value === "string") { // if single value is a %
                  if(key === 'translateY') {
                    value = convertPercentToPx(value, 'y');
                  } else {
                    value = convertPercentToPx(value, 'x');
                  }
                }
              }
              keyframes[i].animations[j][key] = value;
            }
          });
        }
      }
    }

    getDefaultPropertyValue = function(property) {
      switch (property) {
        case 'translateX':
          return 0;
        case 'translateY':
          return 0;
        case 'scale':
          return 1;
        case 'rotate':
          return 0;
        case 'opacity':
          return 1;
        default:
          return null;
      }
    }

    /*  Animation/Scrolling
    -------------------------------------------------- */
    updatePage = function() {
      window.requestAnimationFrame(function() {
        setScrollTops();
        if(scrollTop > 0 && scrollTop <= (bodyHeight - windowHeight)) {
          animateElements();
          setKeyframe();
        }
      });
    }

    setScrollTops = function() {
      scrollTop = $window.scrollTop();
      relativeScrollTop = scrollTop - prevKeyframesDurations;
    }

    animateElements = function() {
      var animation, translateY, translateX, scale, rotate, opacity;
      for(var i=0;i<keyframes[currentKeyframe].animations.length;i++) {
        animation   = keyframes[currentKeyframe].animations[i];
        translateY  = calcPropValue(animation, 'translateY');
        translateX  = calcPropValue(animation, 'translateX');
        scale       = calcPropValue(animation, 'scale');
        rotate      = calcPropValue(animation, 'rotate');
        opacity     = calcPropValue(animation, 'opacity');

        $(animation.selector).css({
          'transform':    'translate3d(' + translateX +'px, ' + translateY + 'px, 0) scale('+ scale +') rotate('+ rotate +'deg)',
          'opacity' : opacity
        })
      }
    }

    calcPropValue = function(animation, property) {
      var value = animation[property];
      if(value) {
        value = easeInOutQuad(relativeScrollTop, value[0], (value[1]-value[0]), keyframes[currentKeyframe].duration);
      } else {
        value = getDefaultPropertyValue(property);
      }
      // value = +value.toFixed(2) 
      // TEMPORARILY REMOVED CAUSE SCALE DOESN'T WORK WITHA AGRESSIVE ROUNDING LIKE THIS
      return value;
    }

    easeInOutQuad = function (t, b, c, d) {
      //sinusoadial in and out
      return -c/2 * (Math.cos(Math.PI*t/d) - 1) + b;
    };

    setKeyframe = function() {
      if(scrollTop > (keyframes[currentKeyframe].duration + prevKeyframesDurations)) {
          prevKeyframesDurations += keyframes[currentKeyframe].duration;
          currentKeyframe++;
          showCurrentWrappers();
      } else if(scrollTop < prevKeyframesDurations) {
          currentKeyframe--;
          prevKeyframesDurations -= keyframes[currentKeyframe].duration;
          showCurrentWrappers();
      }
    }

    showCurrentWrappers = function() {
      var i;
      if(keyframes[currentKeyframe].wrapper != currentWrapper) {
        $(currentWrapper).hide();
        $(keyframes[currentKeyframe].wrapper).show();
        currentWrapper = keyframes[currentKeyframe].wrapper;
      }
    }

    /*  Helpers
    -------------------------------------------------- */

    convertPercentToPx = function(value, axis) {
      if(typeof value === "string" && value.match(/%/g)) {
        if(axis === 'y') value = (parseFloat(value) / 100) * windowHeight;
        if(axis === 'x') value = (parseFloat(value) / 100) * windowWidth;
      }
      return value;
    }

    throwError = function() {
      $body.addClass('page-error')
    }

    isTouchDevice = function() {
      return 'ontouchstart' in window // works on most browsers 
      || 'onmsgesturechange' in window; // works on ie10
    }

    init();

  })
}).call(this);

External CSS

  1. //ajax.googleapis.com/ajax/libs/jqueryui/1.11.2/themes/smoothness/jquery-ui.css

External JavaScript

  1. //cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js
  2. //ajax.googleapis.com/ajax/libs/jqueryui/1.11.2/jquery-ui.min.js