Changing Styles Dynamically

element.classList.add('highlight');
element.classList.remove('hidden');
element.classList.toggle('active');
element.classList.contains('selected');

add()
remove()
toggle()
The classList.toggle() method toggles a class on an element. If the class exists, it removes it; if it doesn't exist, it adds it. This is particularly useful for interactive features like showing/hiding elements or changing states. The method returns a boolean indicating whether the class is now present (true) or not (false). You can also pass a second boolean parameter to force adding or removing the class.
contains()