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                <section class="bcls-section">
  <h2 id="app">Get an Access Token</h2>


    <p>Client ID: <input id="clientId" type="text" size="50" /></p>

    <p>Client Secret: <input id="clientSecret" type="text" size="50" /></p>

    <p><button id="submitButton" class="bcls-button">Get Access Token</button></p>


    <h3>Access token</h3>
    <textarea name="accessToken" id="accessToken" class="bcls-code">Access token will appear here...</textarea>

    <h3>Full response</h3>

    <pre class="line-numbers">
<code id="apiResponse" class="language-json">Full API response will appear here...</code></pre>


                /* * The body style is just for the
 * background color of the codepen.
 * Do not include in your code.
body {
  background-color: #111;
  color: #f5f5f5;
  font-family: sans-serif;
  margin: 2em;
 * Styles essential to the sample
 * are below
.bcls-code {
  color: #111;
  font-family: monospace;
  padding: 1em;
  width: 90%;
  min-height: 5em;
  background-color: #fff;
  font-size: 1rem;
.bcls-button {
  padding: .5em;
  background-color: #333;
  border: 1px yellow solid;
  border-radius: .5em;
  color: yellow;
  cursor: pointer;
fieldset {
  color: #64AAB2;
  border: 1px #64AAB2 solid;
  border-radius: .5em;
code {
  color: #E4B842;
  font-family: monospace;


                var BCLS = ( function (window, document) {
  var clientId   = document.getElementById('clientId'),
    clientSecret = document.getElementById('clientSecret'),
    submitButton = document.getElementById('submitButton'),
    accessToken  = document.getElementById('accessToken'),
    apiResponse  = document.getElementById('apiResponse'),
    options      = {},
    proxyURL     = '',

// event handlers
submitButton.addEventListener('click', function() {
  var responseParsed;
  if (isDefined(clientId.value) && isDefined(clientSecret.value)) {
    options.client_id     = clientId.value;
    options.client_secret = clientSecret.value;
    makeRequest(options, function(response) {
      if (isJson(response)) {
        responseParsed          = JSON.parse(response);
        access_token            = responseParsed.access_token;
        accessToken.textContent = access_token;
        apiResponse.textContent = JSON.stringify(responseParsed, null, '  ');
      } else {
        // didn't get JSON back, just dump responseRaw
        apiResponse.textContent = response;
  } else {
    alert('Client id and secret are required.');

accessToken.addEventListener('click', function() {;

 * tests for all the ways a variable might be undefined or not have a value
 * @param {*} x the variable to test
 * @return {Boolean} true if variable is defined and has a value
function isDefined(x) {
    if ( x === '' || x === null || x === undefined) {
        return false;
    return true;

 * tests to see if a string is json
 * @param {String} str string to test
 * @return {Boolean}
function isJson(str) {
    try {
    } catch (e) {
        return false;
    return true;

 * send API request to the proxy
 * @param  {Object} options options for the request
 * @param  {String} requestID the type of request = id of the button
 * @param  {Function} [callback] callback function
function makeRequest(options, callback) {
  var httpRequest = new XMLHttpRequest(),
    // response handler
    getResponse = function() {
      try {
        if (httpRequest.readyState === 4) {
          if (httpRequest.status >= 200 && httpRequest.status < 300) {
            // check for completion
            responseRaw = httpRequest.responseText;
      } catch (e) {
        alert('Caught Exception: ' + e);
  // set up request data
  requestParams = 'client_id=' + options.client_id + '&client_secret=' + options.client_secret;

  // set response handler
  httpRequest.onreadystatechange = getResponse;
  // open the request'POST', proxyURL);
  // set headers
  httpRequest.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
  // open and send request

})(window, document);