How to test various sketches in nested folders

I use browser sync and sublime text to test my sketches.
In a folder named project, I have:
the index.html file (that refers to sketch.js)
the sketch.js file
the p5 folder.

I subsequently made a modification to index and saved it in a folder named draft inside of project.
I made a modification to sketch.js and saved it also in the draft folder
I changed these lines in index.html

    <script src="p5/p5.js"></script>
    <script src="p5/addons/p5.dom.js"></script>

to

    <script src="../p5/p5.js"></script>
    <script src="../p5/addons/p5.dom.js"></script>

because I did not want to duplicate p5.
Unfortunately, nothing renders.
How can I refer to the enclosing folder in a windows path in a way that p5 understands?

The location of the “.html” file is considered the root folder.

We can’t go upper the root folder, but we can go lower into its subfolders.