# Running In A Browser Using WebAssembly The tutorial so far used `cargo run` to build and run the code as a native application. Native applications are the primary target of the Slint framework, but it also supports WebAssembly for demonstration purposes. This section uses the standard rust tool `wasm-bindgen` and `wasm-pack` to run the game in the browser. Read the [wasm-bindgen documentation](https://rustwasm.github.io/docs/wasm-bindgen/examples/without-a-bundler.html) for more about using wasm and rust. Install `wasm-pack` using cargo: ```sh cargo install wasm-pack ``` Edit the `Cargo.toml` file to add the dependencies. ```toml [target.'cfg(target_arch = "wasm32")'.dependencies] wasm-bindgen = { version = "0.2" } getrandom = { version = "0.2.2", features = ["js"] } ``` `'cfg(target_arch = "wasm32")'` ensures that these dependencies are only active when compiling for the wasm32 architecture. Note that the `rand` dependency is now duplicated, to enable the `"wasm-bindgen"` feature. While you are editing the `Cargo.toml`, make one last change. To turn the binary into a library by adding the following: ```toml [lib] path = "src/main.rs" crate-type = ["cdylib"] ``` This is because wasm-pack requires Rust to generate a `"cdylib"`. You also need to change `main.rs` by adding the `wasm_bindgen(start)` attribute to the `main` function and export it with the `pub` keyword: ```rust,noplayground #[cfg_attr(target_arch = "wasm32", wasm_bindgen::prelude::wasm_bindgen(start))] pub fn main() { //... } ``` Compile the program with `wasm-pack build --release --target web`. This creates a `pkg` directory containing several files, including a `.js` file named after the program name that you need to import into an HTML file. Create a minimal `index.html` in the top level of the project that declares a `` element for rendering and loads the generated wasm file. The Slint runtime expects the `` element to have the id `id = "canvas"`. (Replace `memory.js` with the correct file name). ```html ``` Unfortunately, loading ES modules isn't allowed for files on the file system when accessed from a `file://` URL, so you can't load the `index.html`. Instead, you need to serve it through a web server. For example, using Python, by running: ```sh python3 -m http.server ``` Now you can access the game at [http://localhost:8000](http://localhost:8000/).