"use strict"; OB_ready(OB_doWhenReady); function OB_doWhenReady() { // localize everything var ooohBoi = window.ooohBoi || {}; // local scope variables ooohBoi.prev_scroll_pos = window.scrollY || document.body.scrollTop; ooohBoi.cur_scroll_pos; ooohBoi.scroll_direction = 'init'; ooohBoi.prev_scroll_direction = 0; ooohBoi.header = document.querySelector('#show-hide-header'); // header ID ooohBoi.header_pos = { top: ooohBoi.header.offsetTop, left: ooohBoi.header.offsetLeft, }; ooohBoi.header_height = OB_outerHeight(ooohBoi.header); // show-hide header with ease/transition ooohBoi.header.style.transition = 'all 0.3s ease'; // update header height on window resize ooohBoi.updateHeaderHeight = function() { ooohBoi.header_height = OB_outerHeight(ooohBoi.header); } // listen "scroll" event and decide what to do ooohBoi.checkScroll = function() { ooohBoi.cur_scroll_pos = window.scrollY || document.body.scrollTop; if (ooohBoi.cur_scroll_pos > ooohBoi.prev_scroll_pos) ooohBoi.scroll_direction = 'down'; else if (ooohBoi.cur_scroll_pos ooohBoi.header_height) { OB_addClass(ooohBoi.header, 'im-hidden'); // for styling ooohBoi.header.style.top = -1 * ooohBoi.header_height + "px"; ooohBoi.prev_scroll_direction = scroll_direction; } else if (scroll_direction === 'up') { OB_removeClass(ooohBoi.header, 'im-hidden'); ooohBoi.header.style.top = ooohBoi.header_pos.top + "px"; ooohBoi.prev_scroll_direction = scroll_direction; } } // listen "scroll" and "resize" window events window.addEventListener('scroll', ooohBoi.checkScroll); window.addEventListener('resize', ooohBoi.updateHeaderHeight); } function OB_outerHeight(el) { var height = el.offsetHeight; var style = getComputedStyle(el); height += parseInt(style.marginTop) + parseInt(style.marginBottom); return height; } function OB_addClass(el, className) { if (el.classList) el.classList.add(className); else { var current = el.className, found = false; var all = current.split(' '); for (var i = 0; i < all.length, !found; i++) found = all[i] === className; if (!found) { if (current === '') el.className = className; else el.className += ' ' + className; } } } function OB_removeClass(el, className) { if (el.classList) el.classList.remove(className); else el.className = el.className.replace(new RegExp('(^|\\b)' + className.split(' ').join('|') + '(\\b|$)', 'gi'), ' '); } function OB_ready(fn) { if (document.readyState != 'loading') fn(); else if (document.addEventListener) document.addEventListener('DOMContentLoaded', fn); else { document.attachEvent('onreadystatechange', function() { if (document.readyState != 'loading') fn(); }); } }