JSFiddle - React, Tailwind, and code Playground

by Eeya Otajal

HTML

<p class="result"></p>

<script type="text/javascript" src="https://code.jquery.com/jquery-3.1.1.min.js"></script>

JavaScript

var sSampleBase64Text = 'data:text/plain;base64,MSkgTG9naW4gRGV0YWlscwogPj4gdGNfYWRtaW5fYXllZQogPj4gdHdpbmtsZXMyMnRo';
var mCheckMatchResult = sSampleBase64Text.match(/^(?:[data]{4}:(text|image|application)\/[a-z]*)/);

var sAlertMessage = 'Valid base 64 encode string';
if (mCheckMatchResult === null || mCheckMatchResult.length <= 0) {
     sAlertMessage = 'Not a valid base 64 encode string';
} 

$('.result').append('<p>' + sAlertMessage + '</p>');