JSFiddle - React, Tailwind, and code Playground

HTML

<form>
    <input value="1" type="checkbox" id="admin" name="admin" /><label for="admin">admin</label>
    <input value="2" type="checkbox" id="security32" name="security32" /><label for="security32">security32</label>
    <input value="4" type="checkbox" id="security64" name="security64" /><label for="security64">security64</label>
</form>
<button onclick="determineDownload();">Submit</button>
<div id="errfn"></div>

CSS

input, label, button, div {float: left;}
input, button, div {clear: left;}

JavaScript

function determineDownload() {
    var admin = document.getElementById('admin').checked,
        security32 = document.getElementById('security32').checked,
        security64 = document.getElementById('security64').checked;
    if (!admin && !security32 && !security64) {
        document.getElementById('errfn').innerHTML = 'Make at least one selection';
    } else if (admin && security32 && security64) {
        alert('security32 and admin and security64');
    } else if (security32 && security64) {
        alert('security64 and security32');
    } else if (admin && security32) {
        alert('security32 and admin');
    } else if (admin && security64) {
        alert('security64 and admin');
    } else if (admin) {
        alert('admin is checked');
    } else if (security32) {
        alert('security32 is checked');
    } else if (security64) {
        alert('security64 is checked');
    }
    return false;
}