JSFiddle - React, Tailwind, and code Playground

by iBertel

HTML

<div class="sidewaysHeader"><h4 id="halsa">Hälsa</h4></div>
        <input type="checkbox" value="idrott" id="idrott" name="halsa" /><label for="idrott">Idrott</label><br />
        <input type="checkbox" value="dans" id="dans" name="halsa" /><label for="dans">Dans</label><br />
        <input type="checkbox" value="hemkunskap" id="hemkunskap" name="halsa" /><label for="hemkunskap">Hemkunskap</label><br />
        <input type="checkbox" value="mat-och-boende" id="mat-och-boende" name="halsa" /><label for="mat-och-boende">Mat & Boende</label>

JavaScript

jQuery(".sidewaysHeader h4").click(function() {
        var elems = $('input:checkbox[name="'+ $(this).attr('id') +'"]');
        elems.attr('checked', elems.filter(':checked').length != elems.length);
    });