>>535016762
here's a quick guide to all the important parts off the top of my head
you can also make a per-character background iframe by prefixing "脚本-" to a regex, making the find regex empty, and then stuffing html into it. this works basically like scripts in pic-related

google translate is your friend here btw
https://n0vi028.github.io/JS-Slash-Runner-Doc/guide/%E5%9F%BA%E6%9C%AC%E7%94%A8%E6%B3%95/%E5%A6%82%E4%BD%95%E6%AD%A3%E7%A1%AE%E4%BD%BF%E7%94%A8%E9%85%92%E9%A6%86%E5%8A%A9%E6%89%8B.html