JSFiddle - React, Tailwind, and code Playground

HTML

Today's date in YYYY-MM-DD format: <span id="today">hjkhjkh</span>

JavaScript

Date.prototype.yyyymmdd = function() {         
                                
        var yyyy = this.getFullYear().toString();                                    
        var mm = (this.getMonth()+1).toString(); // getMonth() is zero-based         
        var dd  = this.getDate().toString();             
                            
        return yyyy + '-' + (mm[1]?mm:"0"+mm[0]) + '-' + (dd[1]?dd:"0"+dd[0]);
   };  

d = new Date();
$('#today').html(d.yyyymmdd());