Epub.js v0.3

Epub.js is a JavaScript library for rendering ePub documents in the browser, across many devices.

Epub.js provides an interface for common ebook functions (such as rendering, persistence and pagination) without the need to develop a dedicated application or plugin. Importantly, it has an incredibly permissive Free BSD license.

Try it while reading Moby Dick

Why EPUB

The EPUB standard is a widely used and easily convertible format. Many books are currently in this format, and it is convertible to many other formats (such as PDF, Mobi and iBooks).

An unzipped EPUB3 is a collection of HTML5 files, CSS, images and other media – just like any other website. However, it enforces a schema of book components, which allows us to render a book and its parts based on a controlled vocabulary.

More specifically, the EPUB schema standardizes the table of contents, provides a manifest that enables the caching of the entire book, and separates the storage of the content from how it’s displayed.

Getting Started

If using archived .epub files include JSZip (this must precede inclusion of epub.js):

<script src="../dist/jszip.min.js"></script>

Get the minified code from the build folder:

<script src="../dist/epub.min.js"></script>

Set up a element to render to:

<div id="viewer"></div>

Create the new ePub, and then render it to that element:

<script>
    const book = ePub("uri/to/book/")
    const rendition = book.renderTo("viewer", {
        width: 600,
        height: 400
    })
    const displayed = rendition.display()
</script>

Render manager

default

book.renderTo("viewer", {
    manager: "default",
    width: "100%",
    height: "100%"
})

View example

The default manager only displays a single section at a time.

continuous

book.renderTo("viewer", {
    manager: "continuous",
    width: "100%",
    height: "100%"
})

View example

The continuous manager will display as many sections as need to fill the screen, and preload the next section offscreen. This enables seamless swiping / scrolling between pages on mobile and desktop, but is less performant than the default method.

Flow Overrides

paginated (default)

Flow will be based on the settings in the OPF, defaults to paginated.

book.renderTo("viewer", {
    flow: "paginated",
    width: 900,
    height: 600
})

View example

scrolled-doc

book.renderTo("viewer", {
    flow: "scrolled-doc",
    pageWidth: 800
})

View example

Scripted Content

Scripted content, JavasScript the ePub HTML content, is disabled by default due to the potential for executing malicious content.

This is done by sandboxing the iframe the content is rendered into, though it is still recommended to sanitize the ePub content server-side as well.

If a trusted ePub contains interactivity, it can be enabled by setting a sandbox option set in Rendition settings.

<script>
    const rendition = book.renderTo("viewer", {
        width: 600,
        height: 400,
        sandbox: ["allow-same-origin", "allow-scripts"]
    })
</script>

This will allow the sandboxed content to run scripts, but currently makes the sandbox insecure.

Documentation

API documentation is available at docs/index.md

Running Locally

install node.js

Then install the project dependences with npm

npm install

You can run the reader locally with the command

npm run start

Examples

All source code for the examples is located in the examples subdirectory of this repository. However, not all examples are working. Some of them may be outdated. A list of working examples can be found in the examples/index.html document.

Testing

The mocha framework is used for unit testing. All tests are performed in the browser console. First, you need to start the local server with the following command:

npm run start

Then open the page in the browser at: http://localhost:8080/test/

Finally, open the browser console to see the test results.

Building for Distribution

Builds are concatenated and minified using webpack and babel

To generate a new build run

npm run prepare

or to continuously build run

npm run watch

Hooks

Similar to a plugins, epub.js implements events that can be "hooked" into. Thus you can interact with and manipulate the contents of the book.

Examples of this functionality is loading videos from YouTube links before displaying a chapter's contents or implementing annotation.

Hooks require an event to register to and a can return a promise to block until they are finished.

Example hook:

rendition.hooks.content.register((contents, view) => {

    const items = contents.document.querySelectorAll("[video]")

    items.forEach((item) => {
        // do something with the video item
    })
})

The parts of the rendering process that can be hooked into are below.

book.spine.hooks.serialize // Section is being converted to text
book.spine.hooks.content // Section has been loaded and parsed
rendition.hooks.render // Section is rendered to the screen
rendition.hooks.content // Section contents have been loaded
rendition.hooks.unloaded // Section contents are being unloaded

Reader

The reader has moved to its own repo at: epubreader-js