diff --git a/modules/ui.py b/modules/ui.py
index 60e6b1d6e..5af34ecb0 100644
--- a/modules/ui.py
+++ b/modules/ui.py
@@ -38,6 +38,7 @@ warnings.filterwarnings("default" if opts.show_gradio_deprecation_warnings else
 # this is a fix for Windows users. Without it, javascript files will be served with text/html content-type and the browser will not show any UI
 mimetypes.init()
 mimetypes.add_type('application/javascript', '.js')
+mimetypes.add_type('application/javascript', '.mjs')
 
 # Likewise, add explicit content-type header for certain missing image types
 mimetypes.add_type('image/webp', '.webp')