# How to enable this option by default in pdfjs-express-viewer **URL:** \ **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:** 5\ **Page:** 1
**Author:** ![stsantosyasociados](https://avatars.discourse-cdn.com/v4/letter/s/94ad74/32.png) [@stsantosyasociados](https://pdfjs.community/u/stsantosyasociados)\ **Post date:** [March 8, 2022, 5:52pm UTC](https://pdfjs.community/t/how-to-enable-this-option-by-default-in-pdfjs-express-viewer/1455/1 "2022-03-08T17:52:14Z")
hello everygone I use in react js pdf viewer free and need to for default active to option that points in the image that I uploaded /_version_/ ^8.2.1 ![Captura](https://canada1.discourse-cdn.com/flex031/uploads/pdfjscommunity/original/1X/3db4be43a1f4259e0362653a6658b3cd8c40e7da.png) ---
**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")
**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-) 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) ---
**Author:** ![dnavarro](https://yyz1.discourse-cdn.com/flex031/user_avatar/pdfjs.community/dnavarro/32/707_2.png) [@dnavarro](https://pdfjs.community/u/dnavarro)\ **Post date:** [March 8, 2022, 6:22pm UTC](https://pdfjs.community/t/how-to-enable-this-option-by-default-in-pdfjs-express-viewer/1455/4 "2022-03-08T18:22:03Z")
Hi There, Here is a ticket with a similar question. > [@Force tool button panToolButton starting enabled by default](https://pdfjs.community/t/force-tool-button-pantoolbutton-starting-enabled-by-default/1449/4): > > Hi Luigi, Thanks for your question. Here is a code snippet to help you enable the panToolButton. import WebViewer from '@pdftron/pdfjs-express-viewer' WebViewer({ ...options }).then(instance =\> { const { Tools } = instance.Core; const panTool = Tools.ToolNames.PAN; instance.UI.setToolMode(panTool); }) Hope this helps and let me know if this approach works for you. Thank you, Dandara Hope this helps and let me know if this works for you. Thank you, Dandara ---
**Author:** ![stsantosyasociados](https://avatars.discourse-cdn.com/v4/letter/s/94ad74/32.png) [@stsantosyasociados](https://pdfjs.community/u/stsantosyasociados)\ **Post date:** [March 8, 2022, 7:51pm UTC](https://pdfjs.community/t/how-to-enable-this-option-by-default-in-pdfjs-express-viewer/1455/5 "2022-03-08T19:51:41Z")
hello i use to code to sample and it does not work ```javascript useEffect(() => { WebViewer( { licenseKey: "nkrJM83iXlKQYjD8wPcX", path: "/webviewer/lib", initialDoc: "https://firebasestorage.googleapis.com/v0/b/pruebas-juridicapp-abogados.appspot.com/o/Abogados%2FwPMnKZMLVYRp1fUSJDfEKMTVMVn1%2Fcasos%2F6zYAk2A5enNRnjV8abWW%2FDocumentos%2Fdocumento1_.pdf?alt=media&token=325b1cc0-9d3b-474e-b6ad-e0325dfc7228", }, viewer.current ).then((instance) => { // now you can access APIs through the WebViewer instance const { Core } = instance; /*change lenguage */ instance.UI.setLanguage("es"); const panTool = Core.Tools.ToolNames.PAN; instance.UI.setToolMode(panTool); // remove left panel and left panel button from the DOM instance.UI.disableElements([ "textSelectButton", "selectToolButton", "searchButton", "printButton", ]); /*disable Functions */ instance.disableFeatures([instance.Feature.Print]); instance.disableFeatures([instance.Feature.TextSelection]); instance.disableFeatures([instance.Feature.Copy]); instance.disableFeatures([instance.Feature.FilePicker]); // adding an event listener for when a document is loaded Core.documentViewer.addEventListener("documentLoaded", () => { console.log("document loaded", instance.Feature); }); // adding an event listener for when the page number has changed Core.documentViewer.addEventListener( "pageNumberUpdated", (pageNumber) => { console.log(`Page number is: ${pageNumber}`); } ); }); }, []); ``` ---
**Author:** ![dnavarro](https://yyz1.discourse-cdn.com/flex031/user_avatar/pdfjs.community/dnavarro/32/707_2.png) [@dnavarro](https://pdfjs.community/u/dnavarro)\ **Post date:** [March 9, 2022, 4:54pm UTC](https://pdfjs.community/t/how-to-enable-this-option-by-default-in-pdfjs-express-viewer/1455/6 "2022-03-09T16:54:20Z")
Hi There, Please try to use the following code. ```javascript useEffect(() => { WebViewer( { licenseKey: "nkrJM83iXlKQYjD8wPcX", path: "/webviewer/lib", initialDoc: "https://firebasestorage.googleapis.com/v0/b/pruebas-juridicapp-abogados.appspot.com/o/Abogados%2FwPMnKZMLVYRp1fUSJDfEKMTVMVn1%2Fcasos%2F6zYAk2A5enNRnjV8abWW%2FDocumentos%2Fdocumento1_.pdf?alt=media&token=325b1cc0-9d3b-474e-b6ad-e0325dfc7228", }, viewer.current ).then((instance) => { // now you can access APIs through the WebViewer instance const { Core } = instance; /* disable Functions */ instance.disableFeatures([instance.Feature.Print]); instance.disableFeatures([instance.Feature.TextSelection]); instance.disableFeatures([instance.Feature.Copy]); instance.disableFeatures([instance.Feature.FilePicker]); /*change language */ instance.UI.setLanguage("es"); const panTool = Core.Tools.ToolNames.PAN; instance.UI.setToolMode(panTool); // remove left panel and left panel button from the DOM instance.UI.disableElements([ "textSelectButton", "selectToolButton", "searchButton", "printButton", ]); // adding an event listener for when a document is loaded Core.documentViewer.addEventListener("documentLoaded", () => { console.log("document loaded", instance.Feature); }); // adding an event listener for when the page number has changed Core.documentViewer.addEventListener( "pageNumberUpdated", (pageNumber) => { console.log(`Page number is: ${pageNumber}`); } ); }); }, []); ``` I changed the code execution order a bit and it worked on my side. Let me know if this works for you. Thank you, Dandara