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Code Playground

Simple HTML/CSS/JS editor with live iframe preview.

Theory & Scientific Principles

Browser Rendering Pipeline: Web layout engines parse HTML tokens into the Document Object Model (DOM) tree, evaluate CSS rules to generate the CSSOM, compute the Render Tree, execute layout/reflow, and paint raster pixels.

Event Loop & V8 Engine: JavaScript executes single-threaded on the event loop with call stack, microtask queue (Promises), and macrotask queue (setTimeout, DOM events).

Iframe Sandboxing: The right stage hosts an isolated document context that receives live DOM mutations via standard HTML5 document write streams.

Operating Instructions: Write standard HTML, CSS styles, and JavaScript scripts in the editor on the left; the visual stage updates live on key input.

Editor

Live Preview