menu-scroll.js

/**
 *  menu-scroll.js
 * 
 * "Locks" the menu div when it reaches the top of the page. Relies on the class .fixed to the menu bar div 
 *.fixed {
 * position: fixed
 * top: 0;
 * left: 0;
 *}
 */

jQuery(window).scroll(function() {
  var scrollTop = jQuery(this).scrollTop();
  var topMenu = jQuery("#top-menu");
  var pageHeader = jQuery("body").find("#masthead");

  if (scrollTop >= pageHeader.height()) {
    jQuery(topMenu).addClass("fixed");
  } else {
    jQuery(topMenu).removeClass("fixed");
  }
});