rewrite js

index.html

@@ -88,22 +88,27 @@
   </section>
 </main>
 
+
 <script>
-window.addEventListener('DOMContentLoaded', () => {
+window.addEventListener('DOMContentLoaded', function() {
   let link = document.getElementById('soundlink');
   let miku = document.getElementById('miku');
-  if (typeof miku.play == 'function') {
-    function playMiku(e) {
-      miku.play();
-      e.preventDefault();
-    }
 
-    link.href = '#';
-    link.addEventListener('click', playMiku);
+  function play(e) {
+    e.preventDefault();
+    miku.play();
+  }
+
+  // attempt to ensure at least one of the sources is recognised
+  // (and that <audio> is supported)
+  if (!isNaN(miku.duration)) {
+    link.href = '#listen';
+    link.addEventListener('click', play);
   }
 });
 </script>
 
+
 <!--
   - mutant standard emoji by @Dzuque: 👉 https://mutant.tech 👈
     (licensed cc-by-nc-sa 4.0)