code: function _Debugger_upload() {
      return _Scheduler_binding(function(callback) {
        var element = document.createElement("input");
        element.setAttribute("type", "file");
        element.setAttribute("accept", "text/json");
        element.style.display = "none";
        element.addEventListener("change", function(event) {
          var fileReader = new FileReader();
          fileReader.onload = function(e) {
            callback(_Scheduler_succeed(e.target.result));
          };
          fileReader.readAsText(event.target.files[0]);
          document.body.removeChild(element);
        });
        document.body.appendChild(element);
        element.click();
      });
    }
docs: UPLOAD