JSFiddle - React, Tailwind, and code Playground

HTML

<form>
    <input onclick="ATHD()" id="1" type="checkbox" name="pr" />&#160;Password Reset<br />
<input onclick="ATHD()" id="2" type="checkbox" name="ps" />&#160;Password Setup<br />
<input onclick="ATHD()" id="3" type="checkbox" name="fu" />&#160;Firmware Upgrade (if applicable)<br />
<input onclick="ATHD()" id="4" type="checkbox" name="la" />&#160;Local Access Setup<br />
<input onclick="ATHD()" id="5" type="checkbox" name="ra" />&#160;Remote Access Setup<br />
<input onclick="ATHD()" id="6" type="checkbox" name="ma" />&#160;Mobile Access Setup<br />
<input onclick="ATHD()" id="7" type="checkbox" name="rss" />&#160;Recording Schedule Setup<br />
<input onclick="ATHD()" id="8" type="checkbox" name="pb" />&#160;How to playback video<br />
<input onclick="ATHD()" id="9" type="checkbox" name="cv" />&#160;How to convert video<br />
<input onclick="ATHD()" id="10" type="checkbox" name="en" />&#160;Email Notification Setup<br />
<input onclick="ATHD()" id="11" type="checkbox" name="ptz" />&#160;PTZ Setup (if applicable)<br />
<br />
<span style="FONT-WEIGHT: bold">Question</span><span style="COLOR: #ff0000">*</span> (please be specific)<br />
<br />
<textarea style="HEIGHT: 164px; WIDTH: 577px" rows="10" cols="40">
</textarea></p>

<p><button>Continue...</button> 
<textarea style="HEIGHT: 164px; DISPLAY: hidden; WIDTH: 577px" rows="10" cols="40" name="sup">
</textarea>
 &#160;</p>
<input type="hidden" id="hdnValues" />
</form>

JavaScript

// find number of checkboxes (you haven't specified if you 
// have a set number or not. If you have a set number, just 
// set checkboxCount to whatever number you have.
var checkboxCount = 0;
var inputTags = document.getElementsByTagName('input');
for (var i=0, length = inputTags.length; i<length; i++) {
     if (inputTags[i].type == 'checkbox') {
         checkboxCount++;
     }
}

function ATHD() {
    var totalValue = '';
    for (var i = 1; i < checkboxCount; i++) {
        if (document.getElementById(i).checked)
            totalValue += inputTags[i].getAttribute("name") + ';';
    }
    document.getElementById("hdnValues").value = totalValue;
    alert(totalValue);
}