Have you ever looked at any open-source browser implementation? Because of cascading nature of style definition. Data structures describing current styling for

Have you ever looked at any open-source browser implementation? Because of cascading nature of style definition. Data structures describing current styling form trees (for memory efficiency and easy manipulation from script). Effective styles are evaluated during rendering. For example look at this talk and around 11:30 the guy is describing style-related data structure in Chrome/WebKit: http://www.youtube.com/watch?v=RVnARGhhs9w http://www.youtube.com/watch?v=RVnARGhhs9w Your statement "Those style properties exist anyway" is simply not true.