# Running In A Browser Using WebAssembly Right now, we used `cargo run` to build and run our program as a native application. Native applications are the primary target of the Slint framework, but we also support WebAssembly for demonstration purposes. So in this section we'll use the standard rust tool `wasm-bindgen` and `wasm-pack` to run the game in the browser. The [wasm-bindgen](https://rustwasm.github.io/docs/wasm-bindgen/examples/without-a-bundler.html) documentation explains all you need to know about using wasm and rust. Make sure to have `wasm-pack` installed using ```sh cargo install wasm-pack ``` You'll need to edit your `Cargo.toml` to add the dependencies. ```toml [target.'cfg(target_arch = "wasm32")'.dependencies] wasm-bindgen = { version = "0.2" } getrandom = { version = "0.2.2", features = ["js"] } ``` The `'cfg(target_arch = "wasm32")'` ensures that these dependencies will only be active when compiling for the wasm32 architecture. Note that the `rand` dependency is now duplicated, in order to enable the `"wasm-bindgen"` feature. While you are editing the Cargo.toml, one last change is needed: you need to turn the binary into a library by adding the following: ```toml [lib] path = "src/main.rs" crate-type = ["cdylib"] ``` This is required because wasm-pack require rust to generate a `"cdylib"`. You also need to modify the `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() { //... } ``` Now, we can compile our program with `wasm-pack build --release --target web`. This will create a `pkg` directory containing a few files, including a `.js` file named after your program name. We just have to import that from a HTML file. So let's create a minimal `index.html` that declares a `` element for rendering and loads our generated wasm file. The Slint runtime expects the `` element to have the id `id = "canvas"`. (Replace `memory.js` by 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 we can't simply open the index.html. Instead we need to serve it through a web server. For example, using Python, it's as simple as running ```sh python3 -m http.server ``` and then you can now access the game on [http://localhost:8000](http://localhost:8000/).