PyScript, which is, of course, Python in the browser. The tool is in the early experimental phase, so the project doesn’t suggest using it in a production environment yet.

PyScript lets you run Python scripts right in the browser, side by side with JavaScript, with two-way interaction between your code and the web page.

It's possible to take a step further with a browser extension, but this is a basic Python project that hosts a web page that you can drag and drop a file on for a visualizer.

In the December update to Python in Visual Studio Code, developers can experiment with a new preview feature that lets them run and debug Python code in the browser.

Playwright, a Python library, allows developers to essentially control the browser with a few lines of Python code to automate cross-browser testing for single-page web apps and Progressive Web Apps.

Microsoft plans to enable the Python and Ruby languages to be used for client-side development of rich Internet applications that leverage the company’s Silverlight browser plug-in technology ...

Microsoft plans to enable the Python and Ruby languages to be used for client-side development of rich Internet applications that leverage the companyu2019s Silverlight browser plug-in technology.