When you're working with contracts, reports, invoices, manuals, or academic documents, page numbers make navigation much easier.

Instead of manually editing every page, modern JavaScript libraries let you add page numbers directly inside the browser.

In this tutorial, you'll build a browser-based PDF page numbering tool using JavaScript.

Users will be able to upload a PDF, choose where page numbers appear, customize formatting options, preview the document, and download the updated PDF without uploading files to a server.

Everything runs locally inside the browser for better privacy and faster processing.

Table of Contents

How PDF Page Numbering Works

Project Setup

What Library Are We Using?

Creating the Upload Interface

Reading PDF Pages

Previewing Uploaded Pages

Selecting Page Number Position

Choosing Pages to Number

Configuring Number Format and Style

Generating the Updated PDF

Previewing and Downloading the Final PDF

How PDF Page Numbers Help in Real-World Documents

Demo: How the PDF…