JSFiddle - React, Tailwind, and code Playground

by Addy Osmani

HTML

<form>
<input type="checkbox" name="newsletter" checked="checked" value="Hourly" />

    <input type="checkbox" name="newsletter" value="Daily" />
    <input type="checkbox" name="newsletter" value="Weekly" />

    <input type="checkbox" name="newsletter" checked="checked" value="Monthly" />
    <input type="checkbox" name="newsletter" value="Yearly" />
</form>

CSS

div { color:red; }

JavaScript

function countChecked() {
      var n = $("form input:checked").length;
      alert(n + (n <= 1 ? " is" : " are") + " checked!");
    }
    countChecked();
    $(":checkbox").click(countChecked);