JSFiddle - React, Tailwind, and code Playground

HTML

<input type="datetime" id="datepicker" value="2012-10-06T04:13:00+00:00" />

CSS

#datepicker {
    margin: 5px;
    width: 165px;
    height: 25px;
}

JavaScript

alert($('#datepicker').val());

if($('#datepicker').val().match(
    /(\d{4})-(\d{2})-(\d{2})T(\d{2})\:(\d{2})\:(\d{2})[+-](\d{2})\:(\d{2})/
)) {
    alert('ok');
} else {
    alert('not ok');
}