JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://test-api.tokenex.com/inpage/js/TokenEx-Lite.js"></script>
<input id="TxEncryptionKey" type="hidden" value="MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvWpIQFjQQCPpaIlJKpegirp5kLkzLB1AxHmnLk73D3TJbAGqr1QmlsWDBtMPMRpdzzUM7ZwX3kzhIuATV4Pe7RKp3nZlVmcrT0YCQXBrTwqZNh775z58GP2kZs+gVfNqBampJPzSB/hB62KkByhECn6grrRjiAVwJyZVEvs/2vrxaEpO+aE16emtX12RgI5JdzdOiNyZEQteU6zRBRJEocPWVxExaOpVVVJ5+UnW0LcalzA+lRGRTrQJ5JguAPiAOzRPTK/lYFFpCAl/F8wtoAVG1c8zO2NcQ0Pko+fmeidRFxJ/did2btV+9Mkze3mBphwFmvnxa35LF+Cs/XJHDwIDAQAB" />
<input id="txtCreditCard" type="text" value="223345456787455456" />

JavaScript

//grab the public key from the hidden field
var key = document.getElementById('TxEncryptionKey').value;
//grab the PAN
var creditCard = document.getElementById("txtCreditCard").value;

//encrypt the data
var cipherText = TxEncrypt(key, creditCard);
alert(cipherText);