Overview

This article introduces how to limit the User selection field to hold only one value.

By default, User selection fields in Kintone can hold information of multiple users. The number of users that can be selected for the value cannot be controlled with Kintone's built-in features.

Sample Image

The only field needed for this customization to run is the User selection field.

Prepare the App

Create an App with the following fields and settings.

Sample Code

Prepare the following JavaScript code in a text editor and navigate to the Kintone App's settings. Upload the file into the Upload JavaScript for PC option of the JavaScript and CSS Customization settings .

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(function() {
  'use strict';
  var user_selection = 'userfield'; // Set the field code of the User Selection field
  var error_message = 'Only one person in charge can be specified.';

  var myEvent = ['app.record.create.submit', 'app.record.edit.submit', 'app.record.index.edit.submit'];
  kintone.events.on(myEvent, function(event) {
    // Get the User Selection field information
    var record = event.record;
    var selectedUsers = record[user_selection].value;
    if (selectedUsers.length > 1) {
      // If more than one person is specified, set message to error property
      event.error = error_message;
    }
    return event;
  });
})();

Navigate to the Record Create page, Record Edit page or the Record List page. Add 2 or more users to the User selection field and click on Save. The record should be unsaved, and an error message should appear.