Highlight required form fields

Q: I want to style required form fields with no value

A: Use the required form field flag and style your fields as needed.

  1. Set required flag on form fields:

    // Retrieve all form fields.
    const formFields = await instance.getFormFields()
    // Set the `required` property for all form fields.
    const updatedFields = formFields.map(formField => formField.set('required', true))
    // Update the form fields.
    await instance.update(updatedFields)

    PSPDFKit.FormFields.TextFormField, PSPDFKit.FormFields.ComboBoxFormField and PSPDFKit.FormFields.ListBoxFormField with the required flag set will be rendered with the PSPDFKit-Annotation-Widget-Required CSS class and will have the HTML required attribute set.

  2. Use a custom stylesheet to provide your custom CSS:

    const instance = await PSPDFKit.load({
        styleSheets: ['https://example.com/my-stylesheet.css'],
  3. Use :invalid pseudo-class to mark empty required fields:

    <!-- This matches empty required fields. -->
    .PSPDFKit-Annotation-Widget-Required:invalid {
        border: 28
    <!-- This matches filled required fields. -->
    .PSPDFKit-Annotation-Widget-Required {
        border: 1px solid green;

This has been tested with PSPDFKit for Web 2020.6.4