JSFiddle - React, Tailwind, and code Playground

HTML

<input name="v1" type="checkbox" value="t1" checked="checked" />
<input name="v2" type="checkbox" value="t2" checked="checked" />
<input name="v3" type="checkbox" value="t3"  />
<input name="v4" type="checkbox" value="t4" checked="checked" />
<input name="v5" type="checkbox" value="t5"  />
<div id="result">

</div>

JavaScript

var i_l = $('input:checked').length;
console.log(i_l);
$('div#result').html(i_l);