diff --git a/docs/usage/webworker.md b/docs/usage/webworker.md
index 93e5a9fd8..4b3ddbab9 100644
--- a/docs/usage/webworker.md
+++ b/docs/usage/webworker.md
@@ -114,7 +114,7 @@ async function loadPythonPackages(){
     pythonLoading = self.pyodide.loadPackage(['numpy', 'pytz']);
 }
 
-let onmessage = async(event) => {
+self.onmessage = async(event) => {
     await languagePluginLoader;
      // since loading package is asynchronous, we need to make sure loading is done:
     await pythonLoading;