JSFiddle - React, Tailwind, and code Playground

HTML

<div id="div1" class='box'></div>
<div id="div2" class='box'></div>

<h2>Color 1</h2>
<select class='color-selector' data-target='#div1'>
    <option value='red'>Red</option>
    <option selected value='green'>Green</option>
    <option value='blue'>Blue</option>
</select>

<h2>Color 2</h2>
<select class='color-selector' data-target='#div2'>
    <option value='red'>Red</option>
    <option value='green'>Green</option>
    <option selected value='blue'>Blue</option>
</select>

CSS

.box
{
    width: 128px; 
    height :128px; 
    border: solid 1px black;
    display: inline-block;
}

JavaScript

$(function() {
    $('.color-selector').change(function() {
        var target = $(this).attr('data-target');
        var color = $(this).find('option:selected').val();
        $(target).css('background-color', color);
    });
    
    $('.color-selector').change();
})