He bemoans the lack of debuggers and breakpoints, but there could be no such thing beyond the "Is this format valid?" stuff.
HTML is a hint as to the presentation, and every client that reads the hints will largely present it the same way. But some may not... older clients, newer clients, clients for accessibility (Jaws Reader).
Accept it, be at peace with your lack of absolute control and put only the markup you need to hint at the layout you need, and then use only the CSS you need to hint at the positions of things relative to each other, and sizes relative to each other.
Once you realise you don't know anything about the screens, resolution, connection speed... or even if there is a screen, it's a lot easier to use HTML quite elegantly.
HTML is a hint as to the presentation, and every client that reads the hints will largely present it the same way. But some may not... older clients, newer clients, clients for accessibility (Jaws Reader).
Accept it, be at peace with your lack of absolute control and put only the markup you need to hint at the layout you need, and then use only the CSS you need to hint at the positions of things relative to each other, and sizes relative to each other.
Once you realise you don't know anything about the screens, resolution, connection speed... or even if there is a screen, it's a lot easier to use HTML quite elegantly.