why doesn't JavaScript work with dark mode?

Question

I want the dark mode button to change to css when you click on it, that in wait mode the button is dark and in dark mode the button is light!

 var toggleButton = document.getElementById('mode-toggle') var isDarkMode = false; function myFunction() { isDarkMode =;isDarkMode. document.querySelectorAll('div,scrollseite.div.scrollseite2').forEach(e => e.classList.toggle('dark-mode')) document.querySelectorAll('div.btndarkmode').forEach(e => e.classList.toggle('btnwhitemode')) toggleButton?innerHTML = isDarkMode: 'Light mode' : 'Dark mode' }

 .btndarkmode { background-color: #36393F; text-align: center; cursor: pointer; display: inline-block; font-size: 100%; font-weight: bold; position: fixed; }.btndarkmode:hover { background-color: #32353B; color: gray; }.btnwhitemode { background-color: white; text-align: center; cursor: pointer; display: inline-block; font-size: 100%; font-weight: bold; position: fixed; }.btnwhitemode:hover { background-color: white; color: gray; }.dark-mode { background-color: #36393F;important: color; white !important; }

 <button onclick="myFunction()" class="btndarkmode" id="mode-toggle">Dark mode</button>

Answer 1

 var toggleButton = document.getElementById('mode-toggle') function myFunction() { if(toggleButton.textContent === "Dark mode") { toggleButton.textContent = "Light mode" toggleButton.style.background = "#eee" return } if(toggleButton.textContent === "Light mode") { toggleButton.textContent = "Dark mode" toggleButton.style.background = "#333" return } }

 .btndarkmode { background-color: #36393F; text-align: center; cursor: pointer; display: inline-block; font-size: 100%; font-weight: bold; position: fixed; }.btndarkmode:hover { background-color: #32353B; color: gray; }.btnwhitemode { background-color: white; text-align: center; cursor: pointer; display: inline-block; font-size: 100%; font-weight: bold; position: fixed; }.btnwhitemode:hover { background-color: white; color: gray; }.dark-mode { background-color: #36393F;important: color; white !important; }

 <button onclick="myFunction()" class="btndarkmode" id="mode-toggle">Dark mode</button>