JSFiddle - React, Tailwind, and code Playground

by naokiota

HTML

<select id="ddlCategoryName" data-temp="" data-previousCategoryID="">
  <option value="AAA">AAA</option>
  <option value="BBB">BBB</option>
  <option value="CCC">CCC</option>
</select>
<div id="debug">---</div>

JavaScript

var $el = $('#ddlCategoryName');

    $el.change(function() {
        $el.data("previousCategoryID",$el.data("temp"));
        $el.data("temp",$el.val());
        $("#debug").text($el.data("previousCategoryID"));
    });