You can type out any JavaScript code here (see note below for supported features) and see it run step-by-step with beginner-friendly explanations.
The execution engine can execute most ES5 JavaScript code, with added ES6 support for const/let variables and template literals.
The explanation engine can explain basic flow including variables (declaration/assignment), expressions, conditions, some library methods, arrays, functions, and additional support (for features such as loops and objects) is something I'm actively working on.