# Uncaught TypeError: Cannot read properties of undefined (reading 'querySelector')

**URL:** <https://pdfjs.community/t/uncaught-typeerror-cannot-read-properties-of-undefined-reading-queryselector/1952>\
**Category:** Technical Support\
**Created:** [August 15, 2022, 7:40pm UTC](https://pdfjs.community/t/uncaught-typeerror-cannot-read-properties-of-undefined-reading-queryselector/1952 "2022-08-15T19:40:55Z")\
**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:** [August 15, 2022, 7:41pm UTC](https://pdfjs.community/t/uncaught-typeerror-cannot-read-properties-of-undefined-reading-queryselector/1952/3 "2022-08-15T19:41:01Z")

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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 PDF.js Express Plus with NPM - 2) Copy static files](https://pdfjs.express/documentation/get-started/npm#2)-copy-static-files)
- [Integrating PDF.js Express Plus with React - 3. Place WebViewer into a component](https://pdfjs.express/documentation/get-started/react#3.-place-webviewer-into-a-component)
- [Integrating PDF.js Express Viewer with NPM - 2) Copy static files](https://pdfjs.express/documentation/get-started-viewer/npm#2)-copy-static-files)

APIs:
- [PDF.js Express Utilities](https://pdfjs.express/api/utils/index.html#__anchor)
- [UndefinedbeforeDocumentLoaded](https://pdfjs.express/api/namespaces.list.html#event:beforeDocumentLoaded__anchor)
- [ExpressUtils(optionsopt) - # async extract() → {Promise.}](https://pdfjs.express/api/utils/ExpressUtils.html#extract__anchor)

Forums:
- [Am getting this error when loading WebViewer with Vue application](https://pdfjs.community/t/am-getting-this-error-when-loading-webviewer-with-vue-application/1319/1)
- [PDF.js Express Viewer Watermarks](https://pdfjs.community/t/pdf-js-express-viewer-watermarks/1614/1)
- [Parts of PDF text are not displayed - like whiteout has been wiped across](https://pdfjs.community/t/parts-of-pdf-text-are-not-displayed-like-whiteout-has-been-wiped-across/1895/1)

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