# PDF file download progress callback

**URL:** <https://pdfjs.community/t/pdf-file-download-progress-callback/1207>\
**Category:** Technical Support\
**Tags:** pdfjs-express\
**Created:** [November 30, 2021, 3:57pm UTC](https://pdfjs.community/t/pdf-file-download-progress-callback/1207 "2021-11-30T15:57:25Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![driley](https://avatars.discourse-cdn.com/v4/letter/d/13edae/32.png) [@driley](https://pdfjs.community/u/driley)\
**Post date:** [December 1, 2021, 9:42pm UTC](https://pdfjs.community/t/pdf-file-download-progress-callback/1207/4 "2021-12-01T21:42:14Z")

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Hi There,

If you are talking about loading a file from your server to display in the viewer for a user I would suggest looking into implementing [range requests](https://pdfjs.express/documentation/learn-more/best-practices#support-range-requests)

If you are however talking about the user clicking the download button, and downloading their file to their local machine. You will need to create a custom header button and implement that functionality yourself. A good place to start for that would be the [Action Button API](https://pdfjs.express/documentation/ui-customization/customizing-header.8#actionbutton)

Cheers,  
Dustin

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