title: Popup window not scrollable
body: <p>I know this is probably a basic question, but I've tried every solution out there and I can't seem to get my popup window to scroll vertically. </p>
  
  <p>So I have a 'p' element that an individual can click on and show several reviews. The window pops open, however, the text within the popup window extends beyond the bottom without it being scrollable.</p>
  
  <p>Any help to get the window scrollable is appreciated. </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>var modal = document.getElementById('myModal');
  var btn = document.getElementById('myBtn');
  var span = document.getElementsByClassName('close')[0];
  
  btn.onclick = function() {
    modal.style.display = "block";
  }
  
  span.onclick = function() {
    modal.style.display = "none";
  }
  
  window.onclick = function(event) {
    if (event.target == modal) {
      modal.style.display = "none";
    }
  }</code></pre>
  <pre class="snippet-code-css lang-css prettyprint-override"><code>.modal {
    display: none;
    position: fixed;
    z-index: 1;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgb(0, 0, 0);
    background-color: rgba(0, 0, 0, 0.4);
  }
  
  .modal-content {
    background-color: #fefefe;
    margin: 15% auto;
    padding: 20px;
    overflow: auto;
    border: 1px solid #888;
    width: 80%;
  }
  
  .close {
    color: #aaa;
    float: right;
    font-size: 28px;
    font-weight: bold;
  }
  
  .close:hover,
  .close:focus {
    color: black;
    text-decoration: none;
    cursor: pointer;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;p id="myBtn"&gt;See what our customers are saying&lt;/p&gt;
  
  &lt;div id="myModal" class="modal"&gt;
    &lt;div class="modal-content"&gt;
      &lt;span class="close"&gt;&amp;times;&lt;/span&gt;
      &lt;p&gt;...&lt;/p&gt;
      &lt;p&gt;...&lt;/p&gt;
      &lt;p&gt;...&lt;/p&gt;
      &lt;p&gt;...&lt;/p&gt;
    &lt;/div&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>