https://spnews.com/api/design-3222a21e1eb1d8664d3ae5eb0fbafd7c/option.js

1(() => {
2  const registerScrollToTop = () => {
3
4    const scrollIt = (destination, duration = 300) => {
5      const start = window.pageYOffset;
6      const startTime = 'now' in window.performance ? performance.now() : new Date().getTime();
7      const documentHeight = Math.max(document.body.scrollHeight, document.body.offsetHeight, document.documentElement.clientHeight, document.documentElement.scrollHeight, document.documentElement.offsetHeight);
8      const windowHeight = window.innerHeight || document.documentElement.clientHeight || document.getElementsByTagName('body')[0].clientHeight;
9      const destinationOffset = typeof destination === 'number' ? destination : destination.offsetTop;
10      const destinationOffsetToScroll = Math.round(documentHeight - destinationOffset < windowHeight ? documentHeight - windowHeight : destinationOffset);
11
12      if ('requestAnimationFrame' in window === false) {
13        window.scroll(0, destinationOffsetToScroll);
14        return;
15      }
16
17      function scroll() {
18        const now = 'now' in window.performance ? performance.now() : new Date().getTime();
19        const time = Math.min(1, ((now - startTime) / duration));
20        window.scroll(0, Math.ceil((time * (destinationOffsetToScroll - start)) + start));
21
22        if (window.pageYOffset === destinationOffsetToScroll) {
23          return;
24        }
25        requestAnimationFrame(scroll);
26      }
27
28      scroll();
29    }
30
31    const backToTopLink = document.createElement(
32      "a"
33    );
34    backToTopLink.classList.add(
35      "mp-back-to-top"
36    );
37    const clickBackToTop = (e) => {
38      e.preventDefault();
39      scrollIt(0);
40    };
41    backToTopLink.href="#";
42    backToTopLink.innerHTML = "Back to Top";
43    backToTopLink.addEventListener('click', clickBackToTop);
44    const body = document.getElementById('body');
45    body.parentNode.insertBefore(backToTopLink, body.nextSibling);
46    
47    const checkShowScrollButton = () => {
48      // check if we are scrolled down
49      const ScrollButton = document.querySelector('.mp-back-to-top');
50      if (window.scrollY > 0) {
51        ScrollButton.style.display = 'block';
52      } else {
53        ScrollButton.style.display = 'none';
54      }
55    };
56
57    window.addEventListener("scroll", checkShowScrollButton);
58  };
59
60  const winLoad = (callback) => {
61    if (document.readyState === 'complete') {
62      callback();
63    } else {
64      window.addEventListener('load', callback);
65    }
66  };
67
68  winLoad(registerScrollToTop);
69})();(() => {
70  const registerFixedNav = () => {
71    const nav = document.querySelector('#topnav');
72    const topOfNav = nav.offsetTop;
73    const mobileLogoLink = document.createElement('a');
74    const logoToCopy = document.querySelector('link[rel="shortcut icon"]');
75
76    const stickyLogo = document.createElement('img');
77    stickyLogo.setAttribute('alt', 'Home');
78    if (logoToCopy) {
79      stickyLogo.setAttribute('src', logoToCopy.href);
80      stickyLogo.setAttribute('width', 50);
81      stickyLogo.setAttribute('height', 50);
82      mobileLogoLink.append(stickyLogo);
83    }
84    mobileLogoLink.setAttribute('href', document.querySelector('#logo a[rel="home"]').href);
85    mobileLogoLink.classList.add('mp-sticky-logo');
86    // remove existing sticky logo
87    const oldStickyLogo = nav.querySelector('a.mp-sticky-logo');
88    if (oldStickyLogo) nav.removeChild(oldStickyLogo);
89    nav.insertBefore(mobileLogoLink, nav.firstChild);
90
91    const fixNav = () => {
92      if (window.scrollY >= topOfNav) {
93        nav.classList.add('fixed');
94      } else {
95        nav.classList.remove('fixed');
96      }
97    };
98    window.addEventListener('scroll', fixNav);
99  };
100
101  const winLoad = (callback) => {
102    if (document.readyState === 'complete') {
103      callback();
104    } else {
105      window.addEventListener('load', callback);
106    }
107  };
108
109  winLoad(registerFixedNav);
110})();