HTML Div Division
Author: Shawn Modersohn <shawn@shawnmodersohn.com>
2025
License: Creative Commons V4 <https://creativecommons.org/licenses/by/4.0/legalcode.en>

Scope:
	The Programs.html page at www.shawnmodersohn.com/Programs.html is a collection of programs separated by programming language.  As the page gets longer and longer, being able to find a specific program gets to be overwhelming.  I wanted a javascript application that will collapse categories you are not interested in to minimize the number of programs displayed.  Naturally the application is able expand any category that was previously minimized.  There are two scripts, main.js does the necessary pre-loading of the nodes into memory and excol.js handles the expanding and collapsing.  
	
HTML Structure:
	The body tag must have onload=preLoad()
	Any HTML can go above here as your page may require
		<!-- This is the top level nav div, it's button id must be set in main.js as const topControlButton = "" -->
		<div id="nav1">
			<!-- All button text must default to - -->
			<button id="navB1">-</button>
		</div>
		<!-- This is the main div container, it's ID must be set in main.js as const mainDiv = '' -->
		<div id='samplesDiv'>
			<!-- From here down, divs are tracked -->
			<!-- Above each category, must be a nav div with an id -->
			<div id='nav2'>
				<button id='navB2'>-</button>
			</div>
			<!-- Directly below the nav div is a category div with an id -->
			<div id='category1'>
				<!-- html stuff goes here -->
			</div>
			<!-- So on and so forth -->
		</div>
	Any other HTML can go here as your page requires