JSFiddle - React, Tailwind, and code Playground

HTML

<table>
    <tr><th colspan="2">new Date('2014-01-01') - UTC Date outputs:</th></tr>
    <tr><td> toString():</td><td><span id="utcToString"></span></td> </tr>
    <tr><td> toDateString():</td><td><span id="utc-toDateString"></span></td> </tr>
    <tr><td> toUTCDateString():</td><td><span id="utc-toUTCDateString"></span></td> </tr>
    <tr>
        <th colspan="2">new Date(''2014/01/01') - Local Date outputs:</th>
    </tr>
    <tr><td> toString():</td><td><span id="localToString"></span></td> </tr>
    <tr><td> toDateString():</td><td><span id="local-toDateString"></span></td> </tr>
    <tr><td> toUTCDateString():</td><td><span id="local-toUTCDateString"></span></td> </tr>
</table>

CSS

table th{
    text-align: left;
    
}

JavaScript

var utcDate = new Date('2014-01-01') // returns a UTC date
var localDate = new Date('2014/01/01'); // Returns local date

$("#utcToString").html(utcDate.toString());
$("#utc-toDateString").html(toUTCDateString(utcDate));
$("#utc-toUTCDateString").html(toDateString(utcDate));

$("#localToString").html(localDate.toString());
$("#local-toDateString").html(toUTCDateString(utcDate));
$("#local-toUTCDateString").html(toDateString(utcDate));


function toDateString(utcMillis){
    var date = new Date(utcMillis);
    d = date.getDate();
    m = date.getMonth() +1;
    y = date.getFullYear();
    return y + '-' + addLeadingZero(m, 2) + '-' + addLeadingZero(d,2);
}


function toUTCDateString(utcMillis){
    var date = new Date(utcMillis);
    d = date.getUTCDate();
    m = date.getUTCMonth() +1;
    y = date.getUTCFullYear();
    return y + '-' + addLeadingZero(m, 2) + '-' + addLeadingZero(d,2);
}

function addLeadingZero(n, length){
   n = n+'';
   if(n.length<length)
      return addLeadingZero('0'+n, length--);
   else
      return n;
}