simplify a bunch of code

Cargo.toml

@@ -42,3 +42,4 @@ instant = { version = "0.1.12", features = ["wasm-bindgen"] }
 console_error_panic_hook = "0.1.7"
 wee_alloc = "0.4.5"
 wasm-bindgen = { version = "0.2.79", default-features = false, features = ["std"] }
+web-sys = "0.3.56"

src/egui_app.rs

@@ -98,6 +98,17 @@ lazy_static::lazy_static! {
     };
 }
 
+cfg_if::cfg_if! {
+    if #[cfg(target_arch = "wasm32")] {
+        use wasm_bindgen::JsCast;
+        fn stop_loading() {
+            let document = web_sys::window().unwrap().document().unwrap();
+            let loading_element = document.get_element_by_id("loading").unwrap().dyn_into::<web_sys::HtmlElement>().unwrap();
+            loading_element.remove();
+        }
+    }
+}
+
 // Used when displaying supported expressions in the Help window
 const HELP_EXPR: &str = "- sqrt(x): square root of x
 - abs(x): absolute value of x
@@ -362,7 +373,10 @@ impl epi::App for MathApp {
     fn name(&self) -> &str { "(Yet-to-be-named) Graphing Software" }
 
     // Called once before the first frame.
-    fn setup(&mut self, _ctx: &Context, _frame: &Frame, _storage: Option<&dyn Storage>) {}
+    fn setup(&mut self, _ctx: &Context, _frame: &Frame, _storage: Option<&dyn Storage>) {
+        #[cfg(target_arch = "wasm32")]
+        stop_loading();
+    }
 
     // Called each time the UI needs repainting, which may be many times per second.
     #[inline(always)]

src/lib.rs

@@ -14,8 +14,8 @@ cfg_if::cfg_if! {
         #[global_allocator]
         static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT;
 
-        #[wasm_bindgen]
+        #[wasm_bindgen(start)]
-        pub fn start(canvas_id: &str) -> Result<(), wasm_bindgen::JsValue> {
+        pub fn start() -> Result<(), wasm_bindgen::JsValue> {
             log_helper("Initializing...");
 
             // Used in order to hook into `panic!()` to log in the browser's console
@@ -27,7 +27,7 @@ cfg_if::cfg_if! {
 
             log_helper("Starting App...");
             let app = egui_app::MathApp::default();
-            eframe::start_web(canvas_id, Box::new(app))
+            eframe::start_web("canvas", Box::new(app))
         }
     }
 }

www/index.html

@@ -24,8 +24,6 @@
 
             async function run() {
                 await init();
-                document.getElementById("loading").remove();
-                start("canvas");
             }
             run();
         </script>