<script>
    document.getElementById("upload_widget_opener").addEventListener("click", function () {
      cloudinary.openUploadWidget({
        cloud_name: 'your_cloud_name',
        upload_preset: 'your_upload_preset',
        max_image_width: 300,
        max_image_height: 300,
        crop: 'limit'
      },
        function (error, result) {
          console.log(error, result)
          // Push URL into text input
          document.getElementById('url_text').value = result[0].url;
          res.redirect("/files");
        });
    }, false);
  </script>