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HTML

              
                <html>

<head>
  <link href='https://fonts.googleapis.com/css?family=Oswald:400,300,700' rel='stylesheet' type='text/css'>
</head>

<body>
  <div class="content">
    <div class="wrapper">
      <div class="box box1">
        <h1 id="box1">box 1</h1>
      </div>
      <div class="box box2">
        <h1>box 2</h1>
      </div>
      <div class="box box3">
        <h1>box 3</h1>
      </div>
    </div>
  </div>
  <div class="directions">Scroll the boxes left and right.</div>
</body>

</html>
              
            
!

CSS

              
                *{
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body{
  height: 100%;
  color: #fff;
  font-family: 'Oswald', sans-serif;
  text-transform: uppercase;
  font-size: 12px;
}

.directions {
  color: #000;
  font-size: 24px;
}

.content{
  position: relative;
  overflow: scroll;
  width: 100%;
}

.wrapper { 
  width: 2700px;
}

.box{
  width: 900px;
  height: 100px;
  float: left;
  position: relative;
}

.sticky-header {
  position: sticky !important;
  left: 0;
}

.box h1{
  padding: 0;
  position: absolute;
  transform: translate3d(0,0,0);
  float: left;
}

.box1{
  background-color: #9b59b6;
}

.box2{
  background-color: #1abc9c;
}

.box3{
  background-color: #e74c3c;
}
              
            
!

JS

              
                /* modernizr 3.2.0 (Custom Build) | MIT  https://modernizr.com/download/?-csspositionsticky-csstransforms-csstransforms3d */
!function(e,n,t){function s(e,n){return typeof e===n}function r(){var e,n,t,r,i,o,a;for(var f in C)if(C.hasOwnProperty(f)){if(e=[],n=C[f],n.name&&(e.push(n.name.toLowerCase()),n.options&&n.options.aliases&&n.options.aliases.length))for(t=0;t<n.options.aliases.length;t++)e.push(n.options.aliases[t].toLowerCase());for(r=s(n.fn,"function")?n.fn():n.fn,i=0;i<e.length;i++)o=e[i],a=o.split("."),1===a.length?Modernizr[a[0]]=r:(!Modernizr[a[0]]||Modernizr[a[0]]instanceof Boolean||(Modernizr[a[0]]=new Boolean(Modernizr[a[0]])),Modernizr[a[0]][a[1]]=r),y.push((r?"":"no-")+a.join("-"))}}function i(e){var n=S.className,t=Modernizr._config.classPrefix||"";if(_&&(n=n.baseVal),Modernizr._config.enableJSClass){var s=new RegExp("(^|\\s)"+t+"no-js(\\s|$)");n=n.replace(s,"$1"+t+"js$2")}Modernizr._config.enableClasses&&(n+=" "+t+e.join(" "+t),_?S.className.baseVal=n:S.className=n)}function o(){return"function"!=typeof n.createElement?n.createElement(arguments[0]):_?n.createElementNS.call(n,"http://www.w3.org/2000/svg",arguments[0]):n.createElement.apply(n,arguments)}function a(){var e=n.body;return e||(e=o(_?"svg":"body"),e.fake=!0),e}function f(e,t,s,r){var i,f,l,u,p="modernizr",d=o("div"),c=a();if(parseInt(s,10))for(;s--;)l=o("div"),l.id=r?r[s]:p+(s+1),d.appendChild(l);return i=o("style"),i.type="text/css",i.id="s"+p,(c.fake?c:d).appendChild(i),c.appendChild(d),i.styleSheet?i.styleSheet.cssText=e:i.appendChild(n.createTextNode(e)),d.id=p,c.fake&&(c.style.background="",c.style.overflow="hidden",u=S.style.overflow,S.style.overflow="hidden",S.appendChild(c)),f=t(d,e),c.fake?(c.parentNode.removeChild(c),S.style.overflow=u,S.offsetHeight):d.parentNode.removeChild(d),!!f}function l(e,n){return!!~(""+e).indexOf(n)}function u(e){return e.replace(/([a-z])-([a-z])/g,function(e,n,t){return n+t.toUpperCase()}).replace(/^-/,"")}function p(e,n){return function(){return e.apply(n,arguments)}}function d(e,n,t){var r;for(var i in e)if(e[i]in n)return t===!1?e[i]:(r=n[e[i]],s(r,"function")?p(r,t||n):r);return!1}function c(e){return e.replace(/([A-Z])/g,function(e,n){return"-"+n.toLowerCase()}).replace(/^ms-/,"-ms-")}function m(n,s){var r=n.length;if("CSS"in e&&"supports"in e.CSS){for(;r--;)if(e.CSS.supports(c(n[r]),s))return!0;return!1}if("CSSSupportsRule"in e){for(var i=[];r--;)i.push("("+c(n[r])+":"+s+")");return i=i.join(" or "),f("@supports ("+i+") { #modernizr { position: absolute; } }",function(e){return"absolute"==getComputedStyle(e,null).position})}return t}function h(e,n,r,i){function a(){p&&(delete j.style,delete j.modElem)}if(i=s(i,"undefined")?!1:i,!s(r,"undefined")){var f=m(e,r);if(!s(f,"undefined"))return f}for(var p,d,c,h,v,g=["modernizr","tspan"];!j.style;)p=!0,j.modElem=o(g.shift()),j.style=j.modElem.style;for(c=e.length,d=0;c>d;d++)if(h=e[d],v=j.style[h],l(h,"-")&&(h=u(h)),j.style[h]!==t){if(i||s(r,"undefined"))return a(),"pfx"==n?h:!0;try{j.style[h]=r}catch(y){}if(j.style[h]!=v)return a(),"pfx"==n?h:!0}return a(),!1}function v(e,n,t,r,i){var o=e.charAt(0).toUpperCase()+e.slice(1),a=(e+" "+k.join(o+" ")+o).split(" ");return s(n,"string")||s(n,"undefined")?h(a,n,r,i):(a=(e+" "+E.join(o+" ")+o).split(" "),d(a,n,t))}function g(e,n,s){return v(e,t,t,n,s)}var y=[],C=[],w={_version:"3.2.0",_config:{classPrefix:"",enableClasses:!0,enableJSClass:!0,usePrefixes:!0},_q:[],on:function(e,n){var t=this;setTimeout(function(){n(t[e])},0)},addTest:function(e,n,t){C.push({name:e,fn:n,options:t})},addAsyncTest:function(e){C.push({name:null,fn:e})}},Modernizr=function(){};Modernizr.prototype=w,Modernizr=new Modernizr;var x=w._config.usePrefixes?" -webkit- -moz- -o- -ms- ".split(" "):[];w._prefixes=x;var S=n.documentElement,_="svg"===S.nodeName.toLowerCase();Modernizr.addTest("csspositionsticky",function(){var e="position:",n="sticky",t=o("a"),s=t.style;return s.cssText=e+x.join(n+";"+e).slice(0,-e.length),-1!==s.position.indexOf(n)});var b="CSS"in e&&"supports"in e.CSS,P="supportsCSS"in e;Modernizr.addTest("supports",b||P);var z=w.testStyles=f,T="Moz O ms Webkit",k=w._config.usePrefixes?T.split(" "):[];w._cssomPrefixes=k;var E=w._config.usePrefixes?T.toLowerCase().split(" "):[];w._domPrefixes=E;var N={elem:o("modernizr")};Modernizr._q.push(function(){delete N.elem});var j={style:N.elem.style};Modernizr._q.unshift(function(){delete j.style}),w.testAllProps=v,w.testAllProps=g,Modernizr.addTest("csstransforms",function(){return-1===navigator.userAgent.indexOf("Android 2.")&&g("transform","scale(1)",!0)}),Modernizr.addTest("csstransforms3d",function(){var e=!!g("perspective","1px",!0),n=Modernizr._config.usePrefixes;if(e&&(!n||"webkitPerspective"in S.style)){var t,s="#modernizr{width:0;height:0}";Modernizr.supports?t="@supports (perspective: 1px)":(t="@media (transform-3d)",n&&(t+=",(-webkit-transform-3d)")),t+="{#modernizr{width:7px;height:18px;margin:0;padding:0;border:0}}",z(s+t,function(n){e=7===n.offsetWidth&&18===n.offsetHeight})}return e}),r(),i(y),delete w.addTest,delete w.addAsyncTest;for(var A=0;A<Modernizr._q.length;A++)Modernizr._q[A]();e.Modernizr=Modernizr}(window,document);

var FixedHeaders;

FixedHeaders = (function() {
  var $scrollContainer, _getActiveHeader, _initValues, _resetHeader, _scrollHeaders, activeHeader, hasCSS3d, hasStickyCSS, headers, init, lastLeft, oldHeader, scroll;
  lastLeft = -1;
  headers = [];
  activeHeader = {};
  oldHeader = {};
  $scrollContainer = void 0;
  hasStickyCSS = Modernizr.csspositionsticky;
  hasCSS3d = Modernizr.csstransforms3d;
  scroll = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.msRequestAnimationFrame || window.oRequestAnimationFrame || function(callback) {
    window.setTimeout(callback, 1000 / 60);
  };

  /**
   * _resetHeader
   *  Resets the last active header to its original position
   *  when scrolling back (to the left)
   * @param {number} offset Pixel value of the new scroll offset
   */
  _resetHeader = function(offset) {
    if (oldHeader.$element && offset < oldHeader.leftBorder) {
      if (hasStickyCSS) {
        oldHeader.$element.removeClass('sticky-header');
      } else if (hasCSS3d) {
        oldHeader.$element.css('transform', 'translate3d(0px, 0px, 0px)');
      } else {
        oldHeader.$element.css('left', '0px');
      }
    }
  };

  /**
   * _getActiveHeader
   * Sets the `activeHeader` based on the current offset. It looks
   * at the bounds set for each header and picks the active one, or
   * if the scroll is in between headers it will set `activeHeader`
   * to an empty object `{}`
   * @param {number} offset Pixel value of the new scroll offset
   */
  _getActiveHeader = function(offset) {
    _.forEach(headers, function(header) {
      if (header.rightBorder >= offset && header.leftBorder <= offset) {
        activeHeader = header;
        return false;
      } else {
        activeHeader = {};
      }
    });
  };

  /**
   * _initValues
  #
   * Creates an array of objects that contains the bounds of each header and the jQuery
   * selector to speed up checks and element queries.
  #
   * Model: {
   *  leftBorder: The left-most position where the header is fixed
   *  rightBorder: The right-most position where the header is fixed
   *  $element: The jQuery selector for the given element
   * }
  #
   * @param {object} $container jQuery selector of the scroll container
   * @param {object} $elements jQuery selector of the headers you want fixed
   */
  _initValues = function($container, $elements) {
    var $header, $parent, leftBorder, rightBorder;
    leftBorder = void 0;
    rightBorder = void 0;
    $header = void 0;
    $parent = void 0;
    $elements.each(function(i) {
      $header = $(this);
      $parent = $header.parent();
      leftBorder = $parent.position().left;
      rightBorder = leftBorder + $parent.width() - $header.width();
      headers.push({
        leftBorder: leftBorder,
        rightBorder: rightBorder,
        $element: $header
      });
    });
  };

  /**
   * _scrollHeaders
   * Animation loop that sets either of the following:
   * - `position: sticky`
   *   For browsers that have `position: sticky` we use the native
   *   sticky implementation and toggle the `.sticky-header` class outlined
   *   in `src/scss/components/_swatches--price.scss`
   * - `transform: translate3d`
   *   For browsers that can use transforms we use the hardware accelerated
   *   translate3d to move the header.
   * - `position: left`
   *   For all other browsers we will update the left position of the header
   *   as the scroll value changes.
   */
  _scrollHeaders = function() {
    var newLeft, newOffset;
    newLeft = $scrollContainer.scrollLeft();
    newOffset = 0;
    if (newLeft === lastLeft && activeHeader !== {}) {
      scroll(_scrollHeaders);
      return false;
    } else {
      lastLeft = newLeft;
    }
    _getActiveHeader(newLeft);
    if (activeHeader.$element) {
      if (hasStickyCSS && !activeHeader.$element.hasClass('sticky-header')) {
        activeHeader.$element.addClass('sticky-header');
      } else if (hasCSS3d && !hasStickyCSS) {
        newOffset = newLeft - activeHeader.leftBorder >>> 0;
        activeHeader.$element.css('transform', 'translate3d(' + newOffset + 'px, 0px, 0px)');
      } else if (!hasStickyCSS && !hasCSS3d) {
        newOffset = newLeft - activeHeader.leftBorder >>> 0;
        activeHeader.$element.css('left', newOffset + 'px');
      }
    }
    if (!_.isEqual(oldHeader, activeHeader)) {
      _resetHeader(newLeft);
      oldHeader = activeHeader;
    }
    lastLeft = newLeft;
    scroll(_scrollHeaders);
  };
  init = function($container, $elements) {
    $scrollContainer = $container;
    _initValues($container, $elements);
    _scrollHeaders();
  };
  return {
    init: init
  };
})();

FixedHeaders.init($('.content'), $('h1'));
              
            
!
999px

Console