If you upload your plain .txt files to Dashingdon, the commands should work whether or not you have either of the .js files downloaded (Edit: When playing or testing the game on Dashingdon).
They are, however, absolutely necessary to use the save system with your local ChoiceScript installation (Edit: for playing or testing offline). They’re also necessary if you’re exporting a compiled .html file instead of uploading .txt files, iirc.
As for using it in your local ChoiceScript installation, let’s see if I can remember this correctly:
First you want to move both .js files into the /web/ folder of your CS installation: the same one where scene.js and ui.js are.
Second, you go into the /mygame/ folder, where the index.html and mygame.js files are. You’re going to need to edit index.html with a text editor (such as, but not limited to, Notepad, Notepad++, etc.)
Once you have that index.html opened in your text editor of choice, you should see a long section that says things like:
<script>window.version="UNKNOWN"</script>
<script src="../version.js"></script>
<script src="../persist.js"></script>
<script src="../alertify.min.js"></script>
<script src="../util.js"></script>
<link href="../style.css" rel="stylesheet" type="text/css">
<style id="dynamic"></style>
<script src="../ui.js"></script>
<script src="../scene.js"></script>
…and so forth, and so on. You need to add two new lines in that section. The new lines should read:
<script src="../smPlugin.js"></script>
<script src="../smPluginMenuAddon.js"></script>
Note: The two new lines must be placed in that order, with smPlugin.js ahead of smPluginMenuAddon.js.
Once you’ve saved that, you should be able to use the save system both on Dashingdon AND locally through ChoiceScript… though not through CSIDE. It’s a cryin’ shame, I tell you.