If any script on your monitored web pages, including library code, sets the JavaScript window.onerror event, add the following method to the page immediately after setting window.onerror:

<script>
ADRUM.listenForErrors()
</script>

The JavaScript Agent (adrum.js) sets window.onerror to listen for uncaught JavaScript errors. If this listener is overwritten, errors are not reported.

The agent invokes your original onerror handler.