JSFiddle - React, Tailwind, and code Playground

by bruceyang

HTML

<select id="ddlCategoryName">
  <option value="volvo">Volvo</option>
  <option value="saab">Saab</option>
  <option value="mercedes">Mercedes</option>
  <option value="audi">Audi</option>
</select>

JavaScript

var $el = $('#ddlCategoryName');
$el.data('previousCategoryID', $el.val());

$el.change(function() {
    //store new value
    var $this = $(this);
    var newValue = $this.data('newVal', $this.val());

    alert("previous: "+$this.data('previousCategoryID'));
    $this.data('previousCategoryID', $this.val());
});