diff --git a/web/app.js b/web/app.js
index 003f594..1823952 100644
--- a/web/app.js
+++ b/web/app.js
@@ -202,6 +202,7 @@ async function boot(file, variant, setStatus) {
     mainScriptUrlOrBlob: qemuUrl.href,
     print: message => { console.log(message); logLine(message); },
     printErr: message => { console.error(message); logLine(message); },
+    stdin: () => null,
   };
   options.preRun = [() => {
     options.FS.mkdir('/bios');