<!DOCTYPE html>
<html>
<head><title>How to Dark Mode in HTML5</title></head>
<body>
<button onclick="darkMode()">Click me</button>
</body>
<script>
function darkMode() {
if (document.body.style.backgroundColor == "black") {
document.body.style.backgroundColor = "white";
} else {
document.body.style.backgroundColor = "black";
}
console.log(document.body.style.backgroundColor); // ctrl + j and you can see which mode you're in
}
</script>
</html>