# How to enable this option by default in pdfjs-express-viewer

**URL:** <https://pdfjs.community/t/how-to-enable-this-option-by-default-in-pdfjs-express-viewer/1455>\
**Category:** Technical Support\
**Tags:** pdfjs-express\
**Created:** [March 8, 2022, 5:52pm UTC](https://pdfjs.community/t/how-to-enable-this-option-by-default-in-pdfjs-express-viewer/1455 "2022-03-08T17:52:14Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![system](https://canada1.discourse-cdn.com/flex031/uploads/pdfjscommunity/original/1X/ffbcd25c7d423db8d5acd5db201c272f4db306dd.png) [@system](https://pdfjs.community/u/system)\
**Post date:** [March 8, 2022, 5:52pm UTC](https://pdfjs.community/t/how-to-enable-this-option-by-default-in-pdfjs-express-viewer/1455/3 "2022-03-08T17:52:19Z")

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**Hello, I’m Ron, an automated tech support bot 🤖**

While you wait for one of our customer support representatives to get back to you, please check out some of these documentation pages:

Guides:
- [Integrating React with PDF.js Express Viewer JavaScript PDF library - Prerequisites](https://pdfjs.express/documentation/get-started-viewer/react#prerequisites)
- [Integrating PDF.js Express Viewer into a new Blazor project - Prerequisites](https://pdfjs.express/documentation/get-started-viewer/blazor/new-project#prerequisites)
- [Adding your license key - PDF.js Express Viewer License Keys](https://pdfjs.express/documentation/get-started/add-license-key#pdf.js-express-viewer-license-keys-<span-class='viewer'></span>)

APIs:
- [PDF.js Express Utilities](https://pdfjs.express/api/utils/index.html#__anchor)
- [Core - enableFullPDF()](https://pdfjs.express/api/Core.html#.enableFullPDF__anchor)
- [Adding a download button](https://pdfjs.express/api/utils/tutorial-Adding%20a%20download%20button.html#__anchor)

Forums:
- [‘instance’ is not defined](https://pdfjs.community/t/instance-is-not-defined/1302/1)
- [The active licence key is not working](https://pdfjs.community/t/the-active-licence-key-is-not-working/1099/1)
- [License key for viewer is not working in an ionic app](https://pdfjs.community/t/license-key-for-viewer-is-not-working-in-an-ionic-app/1436/1)

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