什么是 WebAssembly（WASM）？

Welcome to WebAssembly (WASM) — the engine behind high-performance apps in the browser. It works hand-in-hand with JavaScript, not against it.

At its core, WebAssembly is a binary instruction format for a stack-based virtual machine — compact, fast, and secure, built to run heavy work in the browser.

WASM isn't a new language. It's a compilation target: write in C, C++, Rust, or C#, compile down to WASM, and browsers run it efficiently.

The binary format pays off three ways: smaller files for faster downloads, quick parsing, and near-native execution close to how your CPU thinks.

WASM runs on a stack-based virtual machine: instructions push values onto a stack, operate on them, and push the result back. Simple and fast.

Speed comes from the binary format plus ahead-of-time compilation: browsers translate WASM to machine code up front, so runtime stays close to native.

WASM augments JavaScript rather than replacing it. JS handles the DOM, network, and app logic; WASM takes the compute-heavy jobs that need raw speed.

A quick mental model: push 5, push 3, then add — pop both, sum, push 8. That low-level stack flow is what makes WASM efficient.

WASM shines where speed matters: 3D gaming, video and image editing, scientific simulations, and immersive AR/VR — all running in the browser.

Time for a quick check on your understanding of WebAssembly!

Recap: WASM is a binary format for a stack VM, a compilation target — not a language — bringing near-native speed alongside JS. Next: why it matters.