Sticky Header script

stickyheader.js

var App = (function () {

  // Sticky Header

  var stickyHeader = function (navElement) { // needs the ID of the element
      this.nav = document.getElementById(navElement);
      this.siteBody = document.getElementsByTagName("body")[0];
      this.stuck = false;
      this.stickPoint = this.getDistance();
  };

  stickyHeader.prototype.getDistance = function() {
    var topDist = this.nav.offsetTop;
    return topDist;
  }

  stickyHeader.prototype.checkSticky = function() {
    var distance = this.getDistance() - window.pageYOffset + 104;
    var offset = window.pageYOffset;
    var className = 'headerIsSticky';
    var thisBody = this.siteBody;

    if ( (distance <= 0) && !this.stuck) {
      if (thisBody.classList) {
        thisBody.classList.add(className);
      } else {
        thisBody.className += ' ' + className;
      }
      this.stuck = true;
    } else if (this.stuck && (offset <= this.stickPoint)){
      if (thisBody.classList) {
        thisBody.classList.remove(className);
      } else {
        thisBody.className = thisBody.className.replace(new RegExp('(^|\\b)' + className.split(' ').join('|') + '(\\b|$)', 'gi'), ' ');;
      }
      this.stuck = false;
    }
  }

  // End stickyHeader

  //exporting public functions

  return {
    stickyHeader: stickyHeader
  };

})();

(function($) {
  jQuery(document).ready(function($) {

    var headerSticky = new App.stickyHeader('header'); // passing the ID of the element
    window.onscroll = function() {
      headerSticky.checkSticky();
    }

  });
})(jQuery);