I have a book about HTML 4, but don't know whether to learn about it know or wait for HTML 5 to be finalized (a few years, I believe for it to be finalized). If I do learn HTML 4, what is different between HTML 4 and HTML 5? Don't want to seem to ask a lot of questions, but should I learn HTML (web programmer) or software engineer as a future career (like working hours, salary, because recently, it seems like people believe the web is going to take over everything, with operating systems becoming obsolete).