../../runtime/lib/grid.js location?

<link href="../../runtime/styles/xp/grid.css" rel="stylesheet"
type="text/css" ></link>
<script src="../../runtime/lib/grid.js"></script>

Okay, I got the grid to show with the above lines, but I'm afraid I don't understand the basic code. At first I got a blank table outline, without a grid.

One of the examples must have loaded something, because now it runs whether I use src="../../runtime/lib/grid.js", src="../runtime/lib/grid.js" or src="/runtime/lib/grid.js". It even ran with "src="aa/../../runtime/lib/grid.js" (I have no aa directory!) although it seemed to take extra time to find something on that one.

What are the src tags referencing or navigating from, and how do they find the grid.js file using all these different references? Would it have something to do with my web host's server configuration?

Thanks!

Newcomer