RuntimeX

You need to put one of these lines of code, just above your </body> tag.

Official imports:

<script src="//8w6hh.csb.app/runtimex.js"></script>

<script src="//minecraftpublisher.github.io/RuntimeX/runtimex.js"></script>

CDN import:

Check back later!

Local import:
Download the RuntimeX executable script here
Then, import it using this:

<script src="/path-to-runtimex/runtimex.js"></script>