---
title: "JavaScript PDF viewer with form filler | Nutrient SDK"
canonical_url: "https://www.nutrient.io/guides/web/forms/fill-form-fields/using-the-ui/"
md_url: "https://www.nutrient.io/guides/web/forms/fill-form-fields/using-the-ui.md"
last_updated: "2026-06-08T19:21:59.296Z"
description: "Fill PDF forms interactively with the built-in UI in Nutrient Web SDK. Click form fields to enter values, toggle design mode, and enable field editing in your JavaScript app."
---

# Fill PDF form fields using our JavaScript viewer UI

Form fields can be manually filled directly using the UI. Just focus or press on a form field in order to type on it or modify its value.

[Try for Free](https://www.nutrient.io/sdk/web/getting-started.md)

[Launch Demo](https://www.nutrient.io/demo/pdf-form-fill/)

If the Form Creator component is present in the license, it's possible to set [`ViewState#formDesignMode`](https://www.nutrient.io/api/web/NutrientViewer.ViewState.html#formDesignMode). When `true`, pressing on a form field will select it and enable moving and resizing it, but it will not be possible to change its value until `NutrientViewer.ViewState#formDesignMode` is set to `false`.
---

## Related pages

- [Adding an image to a PDF form using JavaScript](/guides/web/forms/fill-form-fields/add-image.md)
- [Attach a file to a PDF form using JavaScript](/guides/web/forms/fill-form-fields/attach-a-file.md)
- [Dynamic font loading in PDF forms using Nutrient Web SDK](/guides/web/forms/fill-form-fields/dynamic-font-loading.md)
- [Detecting user inputs in PDF forms](/guides/web/forms/fill-form-fields/detect-user-input.md)
- [Import data into PDFs from a database](/guides/web/forms/fill-form-fields/import-from-database.md)
- [Headless form fill](/guides/web/forms/fill-form-fields/headless.md)
- [Import data into PDF forms using Instant JSON](/guides/web/forms/fill-form-fields/import-from-instant-json.md)
- [Import data into PDF form using Web SDK with Document Engine](/guides/web/forms/fill-form-fields/import-from-server-backed.md)
- [Import data into PDF forms using XFDF](/guides/web/forms/fill-form-fields/import-from-xfdf.md)
- [Customizing PDF form permissions](/guides/web/forms/fill-form-fields/permissions.md)
- [Fill PDF forms programmatically using JavaScript](/guides/web/forms/form-filling.md)