You can. Flutter does this by making the app run in a canvas element with WASM.

Look cool, but I was envisioning a more general approach I suppose, not limited to a single specific language/tool. Flutter still outputs a x.js which is interpreted by V8 and runs within the Chrome sandbox, what I meant was more along the line of a supercharged browser able to run e.g. the JRE allowing to run any random java program out there, but then accessed over an URL and requiring no manual "installation"/copying/extracting files or interpreter setup. Same for e.g. a native Dart app. So you would be able to run any native application (given it's built for your platform obviously) within this kind of browser, you could run chrome in it and access the web like usual I suppose?

So I guess just hassle-free native apps with a focus on client/server architecture like websites, running gimp/paint doesn't seem like a good fit for something like this :')

Looks like you're looking for WASM apps then. Native programs including games if they're compiled to WASM can run on the browser.

Ok WASM looks pretty epic. Google Earth browser version works pretty well and this QT example feels pretty native qt.io/web-assembly-example-slate

Any idea of how popular WASM is? I don't feel like I've ever interacted with any WASM app in the wild which seems pretty sad given the possibilities and how bloated websites in general are.

Still in development, basically. It's not used for full GUI apps necessarily, more like to run computations in the background that are then sent back to the HTML/CSS/JS based GUI.

I see. But theoretically say I want to make a web-accessible GUI I could just make it using my favorite native GUI library which supports compiling to WASM and it _should_ work from there cross platform + mobile, right? Thanks for the chat :-)