Eruda is a javascript tool that displays a web developer console directly in the website itself. This allows it to be used to debug errors on other devices, such as the Switch, WiiU, 3DS, etc.
To use it, embed it on the page like this:
<script src="https://cdn.jsdelivr.net/npm/eruda"></script>
<script>eruda.init();</script>
And then click the gear icon in the bottom right of the page. This is really useful if investigating errors that only occur on the device, and no web console is available.
Docs / more info:
https://eruda.liriliri.io/docs/
Screenshot:
