JSFiddle - React, Tailwind, and code Playground
HTML
<form id="form">
<input class="yourclass">
<input class="otherclass yourclass">
</form>
JavaScript
var allHaveClass = $('#form input').length == $('#form input.yourclass').length;
var allHaveClass2 = $('#form input:not(.yourclass)').length == 0;
alert(allHaveClass);
alert(allHaveClass2);