diff --git a/etc/generate-gh-pages b/etc/generate-gh-pages
index 34a587e..85fd91a 100755
--- a/etc/generate-gh-pages
+++ b/etc/generate-gh-pages
@@ -83,7 +83,11 @@ convert="
    const go = new Go();
    WebAssembly
      .instantiateStreaming(fetch('main.wasm'), go.importObject)
-     .then((result) => go.run(result.instance));
+     .then((result) => go.run(result.instance),
+           (error) => {
+             const button = document.getElementById('run');
+             button.textContent = 'ERROR: (' + error + ')';
+           });
 
    function initialized() {
      const button = document.getElementById('run');