## 2 Understanding WebAssembly
### How Does WebAssembly Complement JavaScript?  
JavaScript and Wasm are two powerful technologies that, when used together, can complement each other and provide significant benefits in web development [12]. We next explore how JavaScript and Wasm work together and how they can enhance each other's capabilities.  
* **Performance Enhancement:** JavaScript is the traditional language used in web development, and is known for its versatility and ease of use. However, JavaScript is an interpreted language, which can sometimes result in slower execution compared to lower-level languages such as C and C++. By leveraging Wasm, developers can offload computationally intensive tasks to the Wasm module, resulting in improved performance and responsiveness.
* **Language Compatibility:** JavaScript has a vast ecosystem of libraries, frameworks, and tools that have been developed over the years. It is the language of the web, and many developers are already familiar with it. Wasm, on the other hand, supports multiple programming languages, including C/C++, Rust, and more. This means that developers can utilize their existing codebase written in different languages and compile it to Wasm to run in the browser. This enables developers to reuse and integrate existing code with JavaScript seamlessly.
* **Code Portability:** JavaScript is supported by all modern web browsers, making it highly portable. However, there are cases in which certain algorithms or complex computations are more efficiently implemented in lower-level languages. With Wasm, developers can compile code from these languages into Wasm modules, which can then be executed in any web browser that supports Wasm. This porta  
Figure 3: Wasm binary data format.  
bility allows developers to target multiple platforms without the need for language-specific implementations.
* **Security and Isolation:** JavaScript executes within the browser's sandbox environment, which provides a level of security by preventing direct access to the underlying system resources. Wasm runs within a sandboxed environment as well; however, it provides additional security features such as memory isolation and fine-grained control over resource access. By utilizing Wasm, developers can ensure a higher level of security when executing potentially untrusted code.
* **Extending JavaScript's Capabilities:** Wasm can be used as a complementary technology to extend JavaScript's capabilities. Developers can leverage Wasm modules to perform computationally intensive tasks, data processing, or even run existing software libraries. JavaScript can act as a glue language, interacting with Wasm modules and providing a higher-level interface or handling UI-related tasks.
* **Improved Developer Experience:** Wasm and JavaScript work hand in hand to enhance the developer experience. Developers can utilize their preferred language for different parts of the application, choosing JavaScript for UI interactions, DOM manipulation, and event handling while offloading performance-critical or complex computations to Wasm modules. This division of labor allows developers to write cleaner and more maintainable code and to optimize performance where it matters most.