code: function(buttonOrFileInputOrFile) {
              var inputs, fileInput,
                  fileBlobOrInput = buttonOrFileInputOrFile;
  
              // We want the reference file/blob here if this is a proxy (a file that will be generated on-demand later)
              if (fileBlobOrInput instanceof qq.BlobProxy) {
                  fileBlobOrInput = fileBlobOrInput.referenceBlob;
              }
  
              // If the item is a `Blob` it will never be associated with a button or drop zone.
              if (fileBlobOrInput && !qq.isBlob(fileBlobOrInput)) {
                  if (qq.isFile(fileBlobOrInput)) {
                      return fileBlobOrInput.qqButtonId;
                  }
                  else if (fileBlobOrInput.tagName.toLowerCase() === "input" &&
                      fileBlobOrInput.type.toLowerCase() === "file") {
  
                      return fileBlobOrInput.getAttribute(qq.UploadButton.BUTTON_ID_ATTR_NAME);
                  }
  
                  inputs = fileBlobOrInput.getElementsByTagName("input");
  
                  qq.each(inputs, function(idx, input) {
                      if (input.getAttribute("type") === "file") {
                          fileInput = input;
                          return false;
                      }
                  });
  
                  if (fileInput) {
                      return fileInput.getAttribute(qq.UploadButton.BUTTON_ID_ATTR_NAME);
                  }
              }
          }
docs: Gets the internally used tracking ID for a button.
  
  @param buttonOrFileInputOrFile `File`, `<input type="file">`, or a button container element
  @returns {*} The button's ID, or undefined if no ID is recoverable
  @private