https://weather.com.hk/js/theme.js?v=211

1/**
2 * weather.com.hk — theme.js
3 * Supports dark/light toggle. Default: light.
4 */
5(function () {
6  // Apply saved theme on load (before paint)
7  var saved = 'light';
8  try { saved = localStorage.getItem('wchk-theme') || 'light'; } catch(e) {}
9  applyTheme(saved);
10
11  function applyTheme(mode) {
12    var html = document.documentElement;
13    if (mode === 'light') {
14      html.classList.add('light');
15      html.classList.remove('dark');
16    } else {
17      html.classList.remove('light');
18      html.classList.add('dark');
19    }
20    // Update header toggle button
21    if (document.readyState === 'loading') {
22      document.addEventListener('DOMContentLoaded', updateUI);
23    } else {
24      updateUI();
25    }
26    function updateUI() {
27      var btn = document.getElementById('theme-toggle-btn');
28      if (btn) btn.textContent = mode === 'light' ? '🌙' : '☀️';
29      // Sync settings checkbox
30      var cb = document.getElementById('stg-dark-mode-toggle');
31      if (cb) cb.checked = (mode === 'dark');
32    }
33  }
34
35  // Global: toggle (called by header button)
36  window.toggleTheme = function () {
37    var html = document.documentElement;
38    var next = html.classList.contains('light') ? 'dark' : 'light';
39    try { localStorage.setItem('wchk-theme', next); } catch(e) {}
40    applyTheme(next);
41  };
42
43  // Global: set explicit mode (called by settings checkbox)
44  window.setTheme = function (mode) {
45    try { localStorage.setItem('wchk-theme', mode); } catch(e) {}
46    applyTheme(mode);
47  };
48
49  // Sync checkbox when settings opens
50  window.syncThemeCheckbox = function () {
51    var html = document.documentElement;
52    var cb = document.getElementById('stg-dark-mode-toggle');
53    if (cb) cb.checked = html.classList.contains('dark');
54  };
55})();