JSFiddle - React, Tailwind, and code Playground

HTML

<input type="checkbox" class="compulsory" value="1">1<br>
<input type="checkbox" class="compulsory" value="2">2<br>
<input type="checkbox" class="compulsory" value="3">3<br>

<button id="continue" type="submit">Continue</button>

CSS

.disabled {
	border: 1px solid #999;
	background-color: #ddd;
}

JavaScript

var checkBoxes = $('input.compulsory'),
    submitButton = $('#continue');

checkBoxes.change(function() {
    submitButton.attr("disabled", checkBoxes.is(":not(:checked)"));
    submitButton.addClass('disabled');
        	});