Your comments
What I just noticed: in my screenshot, the back button is labelled "iCloud" while in your screenshot, the back button is labelled "Textastic".
Have you maybe added two folders in iCloud Drive using "Add External Folder…" and are trying to reference from one external folder to the other?
This won't work. It needs to be the same external folder. So you need to add the parent folder that contains the two subfolders that contain your files.
I unzipped your two .zip files into Textastic's "iCloud" location.
Both "relative.html" and "relativeTest.html" work for me.
Here are screenshots from my iPad:



If you want, you can make a .zip file with the ChartClass and ChartUse folder in Textastic and send it to support@textasticapp.com so I can try to reproduce the issue here.
Does it recognize the "../ChartClass/style.css" file?
I just moved the folders from "Local Files" to the "iCloud" location on my iPad and it still works for me.
Not sure what's going on.
Can you please double-check the name of the "ChartClass" folder? Maybe there is a space somewhere (e.g. "ChartClass<space>") or something?
Just to be sure, I tried it out:
In Local Files, I created the folders "Library" and "CanvasPlay".
Then I added the file "script.js" in the "Library" folder with these contents:
window.alert("Test");
I added the file "index.html" in the "CanvasPlay" folder:
<!DOCTYPE HTML> <html> <head> <meta charset="utf-8"> <title>Test</title> <script src="../Library/script.js"></script> </head> <body> </body> </html>
When I preview the "CanvasPlay/index.html" file, it does show the JavaScript alert from "Library/script.js".
Using relative paths should work. Can you please show me the relevant part of your .html file?
Please note that file paths on iOS are case-sensitive. So "Filters" is not the same folder as "filters".
Feel free to do that. There would be much more needed to implement this efficiently and for all supported languages.
Just running a regex on the whole text on potentially every keystroke would not be how I'd approach this.
Also, one of the biggest problems for me is how to do a touch-friendly UI for expanding/collapsing and have big enough touch targets on small iPhone screens while not interfering with text selection.
With Secure ShellFish, I'd recommend to add the server as an external folder to Textastic using the "Add External Folder…" command.
When you then open a file and edit it, Secure ShellFish should automatically upload your changes.
You can trigger a Save with an external keyboard using Cmd-S. Tapping the "…" button in the top right corner also triggers a save.
If that still doesn't upload the file, I would try if a reboot of your device helps.
Let me know how it goes.
Customer support service by UserEcho
So, if you have a folder in iCloud Drive called "Projects" which in turn contains "ChartClass" and "ChartUse", add the "Projects" folder as an external folder to Textastic and it should work.