DOM manipulation is what makes it possible to build web sites that work like applications. When you’re using a web site that changes in response to your inputs (clicks, keypresses, etc.) without having to reload a new page each time, that’s happening through DOM manipulation.
I’ve created a short video series to get you started. In this first video, I’ll teach you to select the element you want to interact with by querying the DOM, how to change CSS classes on an element, and how to style an element.