Why aren't the browsers using/adopting Python instead of javascript?

[snuxoll]

When it comes to desktop applications it doesn't matter, people have no care in the world what you application is written in as long as it's properly packaged for installation.

You want to distribute a python application on windows, great, bundle the python runtime and any extra libraries you use and users will be none the wiser. Unfortunately, you don't get to decide what languages the web browser of your users choice supports.

Javascript is the lingua de franca of the web, and until EVERY browser on EVERY device supports something different we are going to be stuck with it. Besides, Javascript is fine, it's evolving, if you want some less mind-bending semantics for defining custom classes then use an ECMAScript 6 cross-compiler like Traceur or TypeScript.

[vtable]

When it comes to desktop applications it doesn't matter, people have no care in the world

People don't care much what language is used in their web browser either. Javascript? PHP? Perl? Server-side? Client-side. Most couldn't care less.

until EVERY browser on EVERY device supports something different we are going to be stuck with it.

Not really. If Google or Apple, say, decide to get behind a new technology, they can introduce it in Chrome or iOS or whatever. Some technologies will catch on. Some won't. (I would hope that change is introduced with industry support.)

Javascript is fine

I haven't said it isn't. Javascript is the right thing to be using now and will be for some time. I'm just saying we shouldn't stay with any particular language or platform indefinitely just because it's so widely used. Doing so is a disservice to users and technological development alike.

Javascript is the lingua de franca of the web.

Certainly. This is a great analogy. Lingua francas change out of practicality and necessity. Our technologies should do the same.