portfolio/js/jquery.sticky.js

// Sticky Plugin v1.0.3 for jQuery
// =============
// Author: Anthony Garand
// Improvements by German M. Bravo (Kronuz) and Ruud Kamphuis (ruudk)
// Improvements by Leonardo C. Daronco (daronco)
// Created: 02/14/2011
// Date: 07/20/2015
// Website: http://stickyjs.com/
// Description: Makes an element on the page stick on the screen as you scroll
//              It will only set the 'top' and 'position' of your element, you
//              might need to adjust the width in some cases.

(function ($) {
  var slice = Array.prototype.slice; // save ref to original slice()
  var splice = Array.prototype.splice; // save ref to original slice()

  var defaults = {
      topSpacing: 0,
      bottomSpacing: 0,
      className: "is-sticky",
      wrapperClassName: "sticky-wrapper",
      center: false,
      getWidthFrom: "",
      widthFromWrapper: true, // works only when .getWidthFrom is empty
      responsiveWidth: false,
    },
    $window = $(window),
    $document = $(document),
    sticked = [],
    windowHeight = $window.height(),
    scroller = function () {
      var scrollTop = $window.scrollTop(),
        documentHeight = $document.height(),
        dwh = documentHeight - windowHeight,
        extra = scrollTop > dwh ? dwh - scrollTop : 0;

      for (var i = 0; i < sticked.length; i++) {
        var s = sticked[i],
          elementTop = s.stickyWrapper.offset().top,
          etse = elementTop - s.topSpacing - extra;

        //update height in case of dynamic content
        s.stickyWrapper.css("height", s.stickyElement.outerHeight());

        if (scrollTop <= etse) {
          if (s.currentTop !== null) {
            s.stickyElement.css({
              width: "",
              position: "",
              top: "",
            });
            s.stickyElement.parent().removeClass(s.className);
            s.stickyElement.trigger("sticky-end", [s]);
            s.currentTop = null;
          }
        } else {
          var newTop =
            documentHeight -
            s.stickyElement.outerHeight() -
            s.topSpacing -
            s.bottomSpacing -
            scrollTop -
            extra;
          if (newTop < 0) {
            newTop = newTop + s.topSpacing;
          } else {
            newTop = s.topSpacing;
          }
          if (s.currentTop != newTop) {
            var newWidth;
            if (s.getWidthFrom) {
              newWidth = $(s.getWidthFrom).width() || null;
            } else if (s.widthFromWrapper) {
              newWidth = s.stickyWrapper.width();
            }
            if (newWidth == null) {
              newWidth = s.stickyElement.width();
            }
            s.stickyElement
              .css("width", newWidth)
              .css("position", "fixed")
              .css("top", newTop);

            s.stickyElement.parent().addClass(s.className);

            if (s.currentTop === null) {
              s.stickyElement.trigger("sticky-start", [s]);
            } else {
              // sticky is started but it have to be repositioned
              s.stickyElement.trigger("sticky-update", [s]);
            }

            if (
              (s.currentTop === s.topSpacing && s.currentTop > newTop) ||
              (s.currentTop === null && newTop < s.topSpacing)
            ) {
              // just reached bottom || just started to stick but bottom is already reached
              s.stickyElement.trigger("sticky-bottom-reached", [s]);
            } else if (
              s.currentTop !== null &&
              newTop === s.topSpacing &&
              s.currentTop < newTop
            ) {
              // sticky is started && sticked at topSpacing && overflowing from top just finished
              s.stickyElement.trigger("sticky-bottom-unreached", [s]);
            }

            s.currentTop = newTop;
          }
        }
      }
    },
    resizer = function () {
      windowHeight = $window.height();

      for (var i = 0; i < sticked.length; i++) {
        var s = sticked[i];
        var newWidth = null;
        if (s.getWidthFrom) {
          if (s.responsiveWidth === true) {
            newWidth = $(s.getWidthFrom).width();
          }
        } else if (s.widthFromWrapper) {
          newWidth = s.stickyWrapper.width();
        }
        if (newWidth != null) {
          s.stickyElement.css("width", newWidth);
        }
      }
    },
    methods = {
      init: function (options) {
        var o = $.extend({}, defaults, options);
        return this.each(function () {
          var stickyElement = $(this);

          var stickyId = stickyElement.attr("id");
          var stickyHeight = stickyElement.outerHeight();
          var wrapperId = stickyId
            ? stickyId + "-" + defaults.wrapperClassName
            : defaults.wrapperClassName;
          var wrapper = $("<div></div>")
            .attr("id", wrapperId)
            .addClass(o.wrapperClassName);

          stickyElement.wrapAll(wrapper);

          var stickyWrapper = stickyElement.parent();

          if (o.center) {
            stickyWrapper.css({
              width: stickyElement.outerWidth(),
              marginLeft: "auto",
              marginRight: "auto",
            });
          }

          if (stickyElement.css("float") == "right") {
            stickyElement
              .css({ float: "none" })
              .parent()
              .css({ float: "right" });
          }

          stickyWrapper.css("height", stickyHeight);

          o.stickyElement = stickyElement;
          o.stickyWrapper = stickyWrapper;
          o.currentTop = null;

          sticked.push(o);
        });
      },
      update: scroller,
      unstick: function (options) {
        return this.each(function () {
          var that = this;
          var unstickyElement = $(that);

          var removeIdx = -1;
          var i = sticked.length;
          while (i-- > 0) {
            if (sticked[i].stickyElement.get(0) === that) {
              splice.call(sticked, i, 1);
              removeIdx = i;
            }
          }
          if (removeIdx != -1) {
            unstickyElement.unwrap();
            unstickyElement.css({
              width: "",
              position: "",
              top: "",
              float: "",
            });
          }
        });
      },
    };

  // should be more efficient than using $window.scroll(scroller) and $window.resize(resizer):
  if (window.addEventListener) {
    window.addEventListener("scroll", scroller, false);
    window.addEventListener("resize", resizer, false);
  } else if (window.attachEvent) {
    window.attachEvent("onscroll", scroller);
    window.attachEvent("onresize", resizer);
  }

  $.fn.sticky = function (method) {
    if (methods[method]) {
      return methods[method].apply(this, slice.call(arguments, 1));
    } else if (typeof method === "object" || !method) {
      return methods.init.apply(this, arguments);
    } else {
      $.error("Method " + method + " does not exist on jQuery.sticky");
    }
  };

  $.fn.unstick = function (method) {
    if (methods[method]) {
      return methods[method].apply(this, slice.call(arguments, 1));
    } else if (typeof method === "object" || !method) {
      return methods.unstick.apply(this, arguments);
    } else {
      $.error("Method " + method + " does not exist on jQuery.sticky");
    }
  };
  $(function () {
    setTimeout(scroller, 0);
  });
})(jQuery);

$(document).ready(function () {
  $(".navbar").sticky({ topSpacing: 0 });
});