New JavaScript engines like Internet Explorer’s (and now Edge’s) Chakra came along with JIT compilers that took advantage of new processor capabilities and soon rivaled binary code.

Node.js uses Google's V8 JavaScript engine from Chrome to run and execute JavaScript code outside the browser. SEE: Hiring Kit: Python developer (TechRepublic Premium) ...

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.