JSFiddle - React, Tailwind, and code Playground

HTML

<form action="#" method="post" id="theForm">
<fieldset>
    <legend>Create Your Own Pizza</legend>
    <div>
        <label>Toppings</label>
        <input type="checkbox" name="toggle" id="toggle" value="toggle">All/None</input>
        <p>
            <input type="checkbox" name="ham" id="ham" value="ham">Ham</input>
            <input type="checkbox" name="mushrooms" id="mushrooms" value="mushrooms">Mushrooms</input>
            <input type="checkbox" name="onions" id="onions" value="onions">Onions</input>
            <input type="checkbox" name="sausage" id="sausage" value="sausage">Sausage</input>
            <input type="checkbox" name="greenPeppers" id="greenPeppers" value="greenPeppers">Green Peppers</input>
        </p>
    </div>
<input type="checkbox" name="terms" id="terms" required> I agree to the terms, whatever they are.</input>
<input type="submit" name="submit" value="Submit" id="submit"></input>
</fieldset>
<div id="output"></div>
</form>

JavaScript

// Script 10.5 - pizza.js
// This script creates a master checkbox.

// Function called when the checkbox's value changes.
// Function toggles all the other checkboxes.
function toggleCheckboxes() {
'use strict';

// Get the master checkbox's value:
var status = document.getElementById('toggle').checked;

// Get all the checkboxes:
var boxes = document.querySelectorAll('p input[type="checkbox"]');

// Loop through the checkboxes, starting with the second:
for (var i = 0, count = boxes.length; i < count; i++) {

    // Update the checked property:
    boxes[i].checked = status;

} // End of FOR loop.
} // End of toggleCheckboxes() function.

function disabled () {
    if (document.getElementById('terms').checked)
    {document.getElementById('submit').disabled = false;}
    else
    {document.getElementById('submit').disabled = true;}
}

// Establish functionality on window load:
window.onload = function() {
'use strict';

// Add an event handler to the master checkbox:
document.getElementById('toggle').onchange = toggleCheckboxes;

document.getElementById('submit').disabled = disabled;

document.getElementById('terms').onchange = disabled;

};