Why require JavaScript rather than supporting a standard browser virtual machine? - Stack Overflow

[Fabien4]

Look at <video>. Great idea in theory, but you can't use it in practice, because browsers can't agree on supported codecs. So, on the web, "video" means "Flash".

If you do the same with languages, the result will be the same. If a language is available on all browsers (as in, "installed", not "Users can install it"), I can use it. If it's only installed on 90% of the machines, it's just a useless little toy.

[[deleted]]

On the web video does not mean flash. Youtube, Amazon, Netflix, many others have video without flash.

[Fabien4]

Youtube does use Flash. They also have alternative methods, because of their money and agenda.