JSFiddle - React, Tailwind, and code Playground

HTML

<input type="checkbox" class="group1" />
<input type="checkbox" class="group1" />
<input type="checkbox" class="group1" />

<input type="button" id="check" value="CHECK" />

JavaScript

$(function () {
    $('#check').on('click', function () {
        var IsChecked = !! $('.group1:checked').length;
        alert(IsChecked);
    });
});