I have an element which is hidden by using a CSS class named 'hide' (simply display:none).
I want to be able to display this using JS (by removing the display:none).
I need to change the class, but also ensure other classes (if applicable) aren't removed from that element (so it doesn't just replace a 'show' class with all other classes).
I know that document.get.ElementById('element-id').class doesn't do anything.
The hasClass, addClass, and removeClass functions will let you achieve that.