jSpreadsheet plugin Persistence Flag (free) :

Change value of cells and show toolbar. Here server return randomize time to response success

plugins: [
        { name:'persistanceFlag', plugin:jss_persistanceFlag, options: {showOnlyTime: true,css_progress: 'css-spin'} },
],

This plugins are the free plugins available on Repo of JSpreadsheet plugins

Download full version Documentation

get started to use this plugin with this CDN :

<script src="https://cdn.jsdelivr.net/gh/GBonnaire/jspreadsheet-plugins-and-editors@latest/plugins/src/persistanceFlag/index.js"></script>
<style>.css-spin{animation:css-spin 2s infinite linear}@keyframes css-spin{0%{transform:rotate(0deg)}100%{transform:rotate(359deg)}} </style>