wasm-bindgen/examples/dom/src/lib.rs

extern crate wasm_bindgen;
extern crate web_sys;

use wasm_bindgen::prelude::*;

// Called by our JS entry point to run the example
#[wasm_bindgen]
pub fn run() -> Result<(), JsValue> {
    // Use `web_sys`'s global `window` function to get a handle on the global
    // window object.
    let window = web_sys::window().expect("no global `window` exists");
    let document = window.document().expect("should have a document on window");
    let body = document.body().expect("document should have a body");

    // Manufacture the element we're gonna append
    let val = document.create_element("p")?;
    val.set_inner_html("Hello from Rust!");

    body.append_child(&val)?;

    Ok(())
}