ileReader();
          reader.onload = (a) => {
            jsonData = a.target.result;
            postImportData();
          };
          reader.readAsText(file);
        } else {
          if ((importTextField.value || "").trim() != "") {
            jsonData = importTextField.value;
            postImportData();
            return;
          } else {
            error_div.removeAttribute("hidden");
            error_div.innerText = "No valid JSON file is selected and the textarea is empty!";
          