This is a side effect of the fact that the combination of HTML, CSS and JS as we know it is a giant hack. Or rather, they all developed mostly independently and

This is a side effect of the fact that the combination of HTML, CSS and JS as we know it is a giant hack. Or rather, they all developed mostly independently and then sort of kludged together. HTML5, CSS3 and JS all together with common libraries like jQuery or Dojo or YUI is now pretty much resembling a GUI toolkit, and that's probably what it should have been from the start. Too bad we had to reinvent all that all over again the hard way.