Heck, I'd even go so far as to venture that Java webapps run better than WebGL+JS. Perhaps I'm just biased/bitter because the open source radeon driver does nothing good by way of 3D acceleration.
I upload a WebGL demo to github-pages, and publish the URL.
I don't have to worry about code-signing, app-review-process, and don't need to wait days or weeks until the code is 'up'. For iOS this is the only way to get simple demos out.
Users only need to know a URL, they don't need to download or install stuff, they don't need to find the executable after installing, there are no scare-dialogs about installing unsafe executables, no virus scanner warnings, etc...
It removes all of those from the equation, web tech will be available on most platforms i want to use, so i'm free to choose the best for what i want without worrying if a ton of my software is supported.
The arrow buttons on the remote act as up/down/left/right and the "OK" button acts as enter. It actually ended up needing very little in the way of custom code to work, but like i said this was a pretty small toy app.
Still, if you want an example of a real "web app" that runs on all of those platforms, just look at netflix.
Web is an amazing distribution channel. The whole world is a click away from using whatever you build. Think about how technology distribution evolved in the last few years.. We used to buy Encarta/encyclopedia from a retailer. Now, with the web, you get the whole encarta (and more) with a click.
Seriously, I just wasted an hour trying to get Hetzner's KVM java web app to run on my Mac, because after having a couple of tickets closed and finally calling support directly, I was told firmly that the applet was from a third party vendor over whom they had no control, there was no other alternative, and they had no plans to support a better way to access the KVM.
I had to use Safari instead of Chrome, then CAREFULLY upgrade Java making sure Oracle didn't trick me into installing any toolbars, then find the Java control panel in the system preferences, which was just too awesome to be constrained by the limited confines of the Mac system preferences windows, so I had to read about how "The Java Control Panel opens in a separate window" because obviously it is so much more important than all other control panels, so I then pressed the "Reopen the Java Control Panel" button, which did what it promised after a half second pause, then I had to click around to the Security tab to find the Exception Site List, press the "Edit Site List..." button to bring up the "Exception Site List" dialog in all its glory and splendor, then press the "Add" button, then type an https url with a numeric ip address and port number into the field, then click a long series of "OK" buttons window close icons, then go back to the web browser, refresh the page, click through another series of threatening warning dialogs, to finally get a bottom of the barrel KVM applet.
And it was convinced I was using a German keyboard, so I couldn't find the punctuation characters I needed to type shell commands, and the Z and Y keys were switched. I had to press and shift-press every key to make a little table of substitutions, and then punch each character in carefully instead of touch typing.
One new thing I found during my Java adventure: the system Java control panel has an "Advanced" tab, and if you scroll way down to the bottom, there is a checkbox labeled "Suppress sponsor offers when installing or updating Java". It was un-checked by default of course. I suspect it's not actually hooked up, it's just a placebo, and exists to make me lower my guard next time I install a Java update. I'm not falling for it.
[1]http://www.oracle.com/technetwork/java/javase/downloads/inde...
[1] http://gadgets.ndtv.com/apps/news/oracle-says-it-is-killing-...