JSFiddle - React, Tailwind, and code Playground
HTML
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<input type="text" class="preserves-old-value" id="one">
<input type="text" class="preserves-old-value" id="two">
<input type="text" class="preserves-old-value" id="three">
JavaScript
$('.preserves-old-value').change(function(e) {
alert($(e.target).data('oldVal'))
$(e.target).data('oldVal', e.target.value)
})