With the advent of HTML 5, is there a point in using COMET anymore?

Question

I am very tempted to use long wait http or periodic polling by the client to set up pseudo-sockets on the browser side, for an application that would be used publicly.

But then on the 2nd thought, I am thinking HTML 5 is here.

But on the 3rd thought, what is the percentage of browsers out there that remain non-HTML5 within 12 months, 24 months, 36 months? If there are at least 20% of browsers still incapable of HTML5, then I cannot depend on HTML5 because 20% of users not being able to access an application is a significant amount.

What do you think, how would your advice be (to me and to developers in general)?

Q1. Is there any point in rigging in COMET into an application anymore? I am thinking of gwt comet - http://code.google.com/p/gwt-comet/.

Q2. Should we release a new public application within the next 2 months that is dependent on HTML5 sockets and tell non-HTML5 browser users "sorry, your browser version cannot access this application"?

Or should we architect the apps to use communication like GWT RPC?

Q3. I am also very distrustful of long wait http request. I have never used it before but I have a horrible feeling about it. I have been using 10 to 20 second client-side polling. Is long wait http request risky (risk of hanging a browser session)? Does long wait request present any additional security risk?

Answer 1

Well, if you take into account the time it took/its taking to get rid of IE6, I would not rely much on HTML5 for an app that you want the masses to use.

:)

Answer 2

HTML5 is a client side technology - Comet is a server side one. The real question is when will Servlet 3.0 be implemented? that will replace Comet.

Answer 3

If you're interested in being a good citizen, yes, you should absolutely tell people that you don't support their browser in 2 months. The only reason IE6 keeps hanging around is because developers keep bending over backwards to support it, while all they're doing is allowing users to continue to function with a horribly broken and insecure browser. IE8 is reasonably good, and IE9 is great (time to release unclear though), and all the modern Webkit/Opera/Gecko-based browsers are "good enough", and tend to have user bases that upgrade more frequently than IE.

Of course, market penetration is always a big problem, and a consideration when you're trying to make money from a product. I recognize that telling people that their browser sucks isn't always an option, but more people need to consider it - we need to get rid of these legacy browsers, and that won't happen until we stop supporting them.