Don’t browsers already have similar update logic implemented in their HTML DOM? If the DOM tree stays but a property of some element changes, if that property

Don’t browsers already have similar update logic implemented in their HTML DOM? If the DOM tree stays but a property of some element changes, if that property affects size or layout or other visual state of things, the browser will re-render the changed element, along with any dependent elements. Could be many elements when re-layout is needed, could be just one if the only change is color.