title: Sweetalert not working on IE 11, works on FireFox, Chrome
body: <p>I've got a really strange problem with Sweetalert2 when I try to execute it from IE I got nothing showed. I've read on the site SA site to add the polyfill but it doesn't solve the problem.</p>
  
  <p>The strange thing is that if I try the sweealert demo site it works. 
  When I try to invoke from the IE's console the swal('ok') I got the following output that seems to be the class content instead of the exection</p>
  
  <p>Here's my code(I re-defined the alert)</p>
  
  <pre><code>&lt;script type="text/javascript"&gt;
      alert = function (msg, title, type) {
          if (type == null)
              type = 'error';
          if (title == null)
              title = 'Attenzione';
  
          swal({
              title: title,
              text: msg,
              type: type,
              confirmButtonText: 'Ok'
          });
      }
  
      function ShowToastr(message) {
          swal({
              position: 'top-end',
              type: 'success',
              title: message ? message : 'Operazione completata con successo',
              showConfirmButton: false,
              timer: 1500
          });
      }
  &lt;/script&gt;
  </code></pre>
  
  <p>Inside the _Layout.cshtml I've in the head section</p>
  
  <pre><code> &lt;script src="https://cdn.jsdelivr.net/npm/sweetalert2@7.28.11/dist/sweetalert2.all.min.js"&gt;&lt;/script&gt;
  
  &lt;!-- Include a polyfill for ES6 Promises (optional) for IE11, UC Browser and Android browser support --&gt;
  &lt;script src="https://cdn.jsdelivr.net/npm/promise-polyfill@8/dist/polyfill.js"&gt;&lt;/script&gt;
  </code></pre>
  
  <p>And here's what I see when I try to run it from console</p>
  
  <p><a href="https://i.stack.imgur.com/wtm3j.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/wtm3j.png" alt="enter image description here"></a>
  <a href="https://i.stack.imgur.com/FmFtp.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/FmFtp.png" alt="enter image description here"></a></p>
  
  <p>Thanks</p>