#[cfg(target_arch="wasm32")]

 use wasm_bindgen::prelude::*;

 use winit::{

     event::*,

     event_loop::{ControlFlow, EventLoop},

     window::WindowBuilder,

 };

 #[cfg_attr(target_arch="wasm32", wasm_bindgen(start))]

 pub fn run() {

   cfg_if::cfg_if! {

     if #[cfg(target_arch = "wasm32")] {

       std::panic::set_hook(Box::new(console_error_panic_hook::hook));

       console_log::init_with_level(log::Level::Warn).expect("Couldn't initialize logger");

     } else {

       env_logger::init();

     }

   }

   let event_loop = EventLoop::new();

   let window = WindowBuilder::new().build(&event_loop).unwrap();

   #[cfg(target_arch = "wasm32")]

 {

     // Winit prevents sizing with CSS, so we have to set

     // the size manually when on web.

     use winit::dpi::PhysicalSize;

     window.set_inner_size(PhysicalSize::new(450, 400));

     use winit::platform::web::WindowExtWebSys;

     web_sys::window()

         .and_then(|win| win.document())

         .and_then(|doc| {

             let dst = doc.get_element_by_id("wasm-example")?;

             let canvas = web_sys::Element::from(window.canvas());

             dst.append_child(&canvas).ok()?;

             Some(())

         })

         .expect("Couldn't append canvas to document body.");

 }

     event_loop.run(move |event, _, control_flow| match event {

         Event::WindowEvent {

             ref event,

             window_id,

         } if window_id == window.id() => match event {

             WindowEvent::CloseRequested

             | WindowEvent::KeyboardInput {

                 input:

                     KeyboardInput {

                         state: ElementState::Pressed,

                         virtual_keycode: Some(VirtualKeyCode::Escape),

                         ..

                     },

                 ..

             } => *control_flow = ControlFlow::Exit,

             _ => {}

         },

         _ => {}

     });

 }