JSFiddle - React, Tailwind, and code Playground
by gromer
HTML
<form id="formId">
<input type="text" value="Hey" />
<input type="text" id="b" value="Hola" />
</form>
<div id="c"></div>
JavaScript
if ($('#formId input').hasClass('invalid')) {
$('#c').append('Found<br />');
} else {
$('#c').append('Not found<br />');
}
$('#b').addClass('invalid');
if ($('#formId input').hasClass('invalid')) {
$('#c').append('Found<br />');
} else {
$('#c').append('Not found<br />');
}