JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="myul">
    <li><img src="" /></li>
    <li><img src="" /></li>
    <li><img src="" /></li>
</ul>

<input id="btn" type="button" value="click" />

JavaScript

$(function(){

    $("#myul li").click(function(){
        $("#myul li").removeClass('selected');    
        $("#myul li").css('background','none');    
        $(this).css('background','red');   
        $(this).addClass('selected');    
    });

  $('#btn').click(function(){
    alert( $('.selected img').attr('id') );
  });
  
});