3 files changed, 22 insertions, 9 deletions
diff --git a/index.html b/index.html
index 1aad79c..cc13062 100644
--- a/index.html
+++ b/index.html
@@ -13,6 +13,8 @@
       result: <span id='result'></span>
     </p>
 
+    <button onclick='testalert()'>alert</button>
+
     <script src='./main.mjs' type='module'></script>
   </body>
 </html>
diff --git a/main.mjs b/main.mjs
index 086b876..d8fe63a 100644
--- a/main.mjs
+++ b/main.mjs
@@ -4,6 +4,7 @@ async function run() {
     console.debug('run');
     const foo = await init();
     console.debug('init done', foo);
+
     window.calculate = _ => {
         console.debug('calc');
         const inp1 = document.getElementById('number-input1').value;
@@ -11,6 +12,11 @@ async function run() {
         const res = foo.add(parseInt(inp1), parseInt(inp2));
         document.getElementById('result').textContent = res;
     }
+
+    window.testalert = _ => {
+        console.debug('testalert');
+        foo.test_alert('from js');
+    }
 }
 
 document.addEventListener('DOMContentLoaded', run);
diff --git a/src/lib.rs b/src/lib.rs
index 7db4248..7129898 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,17 +1,22 @@
 use wasm_bindgen::prelude::wasm_bindgen;
 
 #[wasm_bindgen]
+extern {
+    fn alert(s: &str);
+
+    // set the namespace so we can use ‘console.debug’
+    #[wasm_bindgen(js_namespace = console)]
+    fn debug(s: &str);
+}
+
+#[wasm_bindgen]
 pub fn add(left: u32, right: u32) -> u32 {
+    debug(&format!("adding the numbers {} and {}",
+        left, right));
     left + right
 }
 
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
-    }
+#[wasm_bindgen]
+pub fn test_alert(s: &str) {
+    alert(s)
 }