Brython

Brython, short for Browser Python, is an open-source implementation of Python 3 that runs in the web browser and aims to replace JavaScript for client-side web scripting.

It consists of a Python interpreter written in JavaScript and a library that exposes the browser's DOM and Web APIs to Python code via a module named browser. This lets Python code manipulate HTML elements, handle events, and interact with the Document Object Model much as JavaScript does.

Usage involves loading Brython's scripts in an HTML page, then writing Python code in script tags labeled with type="text/python" (or "text/python3"). A call to brython() initializes the interpreter on page load. Typical code imports "from browser import document, html" and binds event handlers or creates DOM nodes using Pythonic syntax.

While Brython enables Python development in the browser, it is not a drop-in replacement for JavaScript for all use cases. It runs within the browser's JavaScript environment, and performance is generally slower for computational tasks. The Python standard library is included selectively, and some modules may be limited or unavailable.

Brython is maintained as an open-source project and has an active community. It is one of several efforts to enable Python in the browser, alongside projects such as Pyodide, though Brython emphasizes Pythonic DOM interaction and education-friendly usage.