Add example_web app

demo_web/src/lib.rs

@@ -5,11 +5,14 @@
 use wasm_bindgen::prelude::*;
 
 /// This is the entry-point for all the web-assembly.
+/// This is called once from the HTML.
+/// It loads the app, installs some callbacks, then returns.
+/// You can add more callbacks like this if you want to call in to your code.
 #[wasm_bindgen]
 pub fn start(canvas_id: &str) -> Result<(), wasm_bindgen::JsValue> {
+    let app = egui::DemoApp::default();
     let backend = egui_web::WebBackend::new(canvas_id)?;
-    let app = Box::new(egui::DemoApp::default());
-    let runner = egui_web::AppRunner::new(backend, app)?;
+    let runner = egui_web::AppRunner::new(backend, Box::new(app))?;
     egui_web::start(runner)?;
     Ok(())
 }