# Getting Started

An introduction to PDF.js with examples.

## Introduction

Before downloading PDF.js please take a moment to understand the different layers of the PDF.js project.

Layer | About
--- | ---
Core | The core layer is where a binary PDF is parsed and interpreted. This layer is the foundation for all subsequent layers. It is not documented here because using it directly is considered an advanced usage and the API is likely to change. For an example of using the core layer see the PDF Object Browser
Display | The display layer takes the core layer and exposes an easier to use API to render PDFs and get other information out of a document. This API is what the version number is based on.
Viewer | The viewer is built on the display layer and is the UI for PDF viewer in Firefox and the other browser extensions within the project. It can be a good starting point for building your own viewer. However, we do ask if you plan to embed the viewer in your own site, that it not just be an unmodified version. Please re-skin it or build upon it.

## Download

### Pre-built

Includes the generic build of PDF.js and the viewer.

Stable (v1.0.1040) Beta (v1.1.1)

### Source

To get a local copy of the current code, clone it using git:

    $ git clone git://github.com/mozilla/pdf.js.git pdfjs
    $ cd pdfjs

## File Layout Overview

### Prebuilt

    ├── LICENSE
    ├── build/
    │   ├── pdf.js                             - display layer
    │   └── pdf.worker.js                      - core layer
    └── web/
        ├── cmaps/                             - character maps(required by core)
        ├── compatibility.js                   - polyfills for missing features
        ├── compressed.tracemonkey-pldi-09.pdf - test pdf
        ├── debugger.js                        - helpful pdf debugging features
        ├── images/                            - images for the viewer and annotation icons
        ├── l10n.js                            - localization
        ├── locale/                            - translation files
        ├── viewer.css                         - viewer style sheet
        ├── viewer.html                        - viewer html
        └── viewer.js                          - viewer layer

### Source

    ├── AUTHORS
    ├── CONTRIBUTING.md
    ├── LICENSE
    ├── README.md
    ├── build/                                 - output of build steps (empty)
    ├── docs/                                  - this
    ├── examples/                              - bare bones examples
    ├── extensions/                            - various browser extensions
    ├── external/                              - third party code
    ├── l10n/                                  - translation files
    ├── make.js                                - build script
    ├── package.json
    ├── src/
    │   ├── core/                              - core layer
    │   ├── display/                           - display layer
    │   ├── images/
    │   ├── pdf.js                             - wrapper file that everything is bundled into
    │   ├── shared/                            - shared code between core and display layers
    │   └── worker_loader.js                   - used for developer builds to load worker files
    ├── test/                                  - reference, unit, and font tests
    └── web/                                   - viewer layer

## Trying the Viewer

With the prebuilt or source version open `web/viewer.html` in a browser and the test pdf should load. Note: the worker is not enabled for file:// urls, so use a server. If you’re using the source build and have node, you can run `node make server`.

## More Information

For a further walkthrough of a minimal viewer see the hello world example. More documentation can be found in our wiki too.