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https://github.com/eKoopmans/html2pdf.js

Client-side HTML-to-PDF rendering using pure JS.
https://github.com/eKoopmans/html2pdf.js

canvas client-side html javascript pdf-generation

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Client-side HTML-to-PDF rendering using pure JS.

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# html2pdf.js



html2pdf.js converts any webpage or element into a printable PDF entirely client-side using [html2canvas](https://github.com/niklasvh/html2canvas) and [jsPDF](https://github.com/MrRio/jsPDF).



> :warning: There have been several issues reported in v0.10. They are being investigated but in the meantime you may wish to remain on v0.9.3 ("^0.9.3" in npm, or [use cdnjs for HTML script tags](https://cdnjs.com/libraries/html2pdf.js/0.9.3)).



## Table of contents



- [Getting started](#getting-started)

  - [CDN](#cdn)

  - [Raw JS](#raw-js)

  - [NPM](#npm)

  - [Bower](#bower)

  - [Console](#console)

- [Usage](#usage)

  - [Advanced usage](#advanced-usage)

    - [Workflow](#workflow)

    - [Worker API](#worker-api)

- [Options](#options)

  - [Page-breaks](#page-breaks)

    - [Page-break settings](#page-break-settings)

    - [Page-break modes](#page-break-modes)

    - [Example usage](#example-usage)

  - [Image type and quality](#image-type-and-quality)

- [Progress tracking](#progress-tracking)

- [Dependencies](#dependencies)

- [Contributing](#contributing)

  - [Issues](#issues)

  - [Tests](#tests)

  - [Pull requests](#pull-requests)

- [Credits](#credits)

- [License](#license)



## Getting started



#### CDN



The simplest way to use html2pdf.js is to include it as a script in your HTML by using cdnjs:



```html



```



Using a CDN URL will lock you to a specific version, which should ensure stability and give you control over when to change versions. cdnjs gives you access to [all past versions of html2pdf.js](https://cdnjs.com/libraries/html2pdf.js).



*Note: [Read about dependences](#dependencies) for more information about using the unbundled version `dist/html2canvas.min.js`.*



#### Raw JS



 You may also download `dist/html2pdf.bundle.min.js` directly to your project folder and include it in your HTML with:



```html



```



#### NPM



Install html2pdf.js and its dependencies using NPM with `npm install --save html2pdf.js` (make sure to include `.js` in the package name).



*Note: You can use NPM to create your project, but html2pdf.js **will not run in Node.js**, it must be run in a browser.*



#### Bower



Install html2pdf.js and its dependencies using Bower with `bower install --save html2pdf.js` (make sure to include `.js` in the package name).



#### Console



If you're on a webpage that you can't modify directly and wish to use html2pdf.js to capture a screenshot, you can follow these steps:



1. Open your browser's console (instructions for different browsers [here](https://webmasters.stackexchange.com/a/77337/94367)).

2. Paste in this code:

    ```js

    function addScript(url) {

        var script = document.createElement('script');

        script.type = 'application/javascript';

        script.src = url;

        document.head.appendChild(script);

    }

    addScript('https://cdnjs.cloudflare.com/ajax/libs/html2pdf.js/0.10.1/html2pdf.bundle.min.js');

    ```

3. You may now execute html2pdf.js commands directly from the console. To capture a default PDF of the entire page, use `html2pdf(document.body)`.



## Usage



Once installed, html2pdf.js is ready to use. The following command will generate a PDF of `#element-to-print` and prompt the user to save the result:



```js

var element = document.getElementById('element-to-print');

html2pdf(element);

```



### Advanced usage



Every step of html2pdf.js is configurable, using its new Promise-based API. If html2pdf.js is called without arguments, it will return a `Worker` object:



```js

var worker = html2pdf();  // Or:  var worker = new html2pdf.Worker;

```



This worker has methods that can be chained sequentially, as each Promise resolves, and allows insertion of your own intermediate functions between steps. A prerequisite system allows you to skip over mandatory steps (like canvas creation) without any trouble:



```js

// This will implicitly create the canvas and PDF objects before saving.

var worker = html2pdf().from(element).save();

```



#### Workflow



The basic workflow of html2pdf.js tasks (enforced by the prereq system) is:



```

.from() -> .toContainer() -> .toCanvas() -> .toImg() -> .toPdf() -> .save()

```



#### Worker API



| Method       | Arguments          | Description |

|--------------|--------------------|-------------|

| from         | src, type          | Sets the source (HTML string or element) for the PDF. Optional `type` specifies other sources: `'string'`, `'element'`, `'canvas'`, or `'img'`. |

| to           | target             | Converts the source to the specified target (`'container'`, `'canvas'`, `'img'`, or `'pdf'`). Each target also has its own `toX` method that can be called directly: `toContainer()`, `toCanvas()`, `toImg()`, and `toPdf()`. |

| output       | type, options, src | Routes to the appropriate `outputPdf` or `outputImg` method based on specified `src` (`'pdf'` (default) or `'img'`). |

| outputPdf    | type, options      | Sends `type` and `options` to the jsPDF object's `output` method, and returns the result as a Promise (use `.then` to access). See the [jsPDF source code](https://rawgit.com/MrRio/jsPDF/master/docs/jspdf.js.html#line992) for more info. |

| outputImg    | type, options      | Returns the specified data type for the image as a Promise (use `.then` to access). Supported types: `'img'`, `'datauristring'`/`'dataurlstring'`, and `'datauri'`/`'dataurl'`. |

| save         | filename           | Saves the PDF object with the optional filename (creates user download prompt). |

| set          | opt                | Sets the specified properties. See [Options](#options) below for more details. |

| get          | key, cbk           | Returns the property specified in `key`, either as a Promise (use `.then` to access), or by calling `cbk` if provided. |

| then         | onFulfilled, onRejected | Standard Promise method, with `this` re-bound to the Worker, and with added progress-tracking (see [Progress](#progress) below). Note that `.then` returns a `Worker`, which is a subclass of Promise. |

| thenCore     | onFulFilled, onRejected | Standard Promise method, with `this` re-bound to the Worker (no progress-tracking). Note that `.thenCore` returns a `Worker`, which is a subclass of Promise. |

| thenExternal | onFulfilled, onRejected | True Promise method. Using this 'exits' the Worker chain - you will not be able to continue chaining Worker methods after `.thenExternal`. |

| catch, catchExternal | onRejected | Standard Promise method. `catchExternal` exits the Worker chain - you will not be able to continue chaining Worker methods after `.catchExternal`. |

| error        | msg                | Throws an error in the Worker's Promise chain. |



A few aliases are also provided for convenience:



| Method    | Alias     |

|-----------|-----------|

| save      | saveAs    |

| set       | using     |

| output    | export    |

| then      | run       |



## Options



html2pdf.js can be configured using an optional `opt` parameter:



```js

var element = document.getElementById('element-to-print');

var opt = {

  margin:       1,

  filename:     'myfile.pdf',

  image:        { type: 'jpeg', quality: 0.98 },

  html2canvas:  { scale: 2 },

  jsPDF:        { unit: 'in', format: 'letter', orientation: 'portrait' }

};



// New Promise-based usage:

html2pdf().set(opt).from(element).save();



// Old monolithic-style usage:

html2pdf(element, opt);

```



The `opt` parameter has the following optional fields:



|Name        |Type            |Default                         |Description                                                                                                 |

|------------|----------------|--------------------------------|------------------------------------------------------------------------------------------------------------|

|margin      |number or array |`0`                             |PDF margin (in jsPDF units). Can be a single number, `[vMargin, hMargin]`, or `[top, left, bottom, right]`. |

|filename    |string          |`'file.pdf'`                    |The default filename of the exported PDF.                                                                   |

|pagebreak   |object          |`{mode: ['css', 'legacy']}`     |Controls the pagebreak behaviour on the page. See [Page-breaks](#page-breaks) below.                        |

|image       |object          |`{type: 'jpeg', quality: 0.95}` |The image type and quality used to generate the PDF. See [Image type and quality](#image-type-and-quality) below.|

|enableLinks |boolean         |`true`                          |If enabled, PDF hyperlinks are automatically added ontop of all anchor tags.                                |

|html2canvas |object          |`{ }`                           |Configuration options sent directly to `html2canvas` ([see here](https://html2canvas.hertzen.com/configuration) for usage).|

|jsPDF       |object          |`{ }`                           |Configuration options sent directly to `jsPDF` ([see here](http://rawgit.com/MrRio/jsPDF/master/docs/jsPDF.html) for usage).|



### Page-breaks



html2pdf.js has the ability to automatically add page-breaks to clean up your document. Page-breaks can be added by CSS styles, set on individual elements using selectors, or avoided from breaking inside all elements (`avoid-all` mode).



By default, html2pdf.js will respect most CSS [`break-before`](https://developer.mozilla.org/en-US/docs/Web/CSS/break-before), [`break-after`](https://developer.mozilla.org/en-US/docs/Web/CSS/break-after), and [`break-inside`](https://developer.mozilla.org/en-US/docs/Web/CSS/break-inside) rules, and also add page-breaks after any element with class `html2pdf__page-break` (for legacy purposes).



#### Page-break settings



|Setting   |Type            |Default             |Description |

|----------|----------------|--------------------|------------|

|mode      |string or array |`['css', 'legacy']` |The mode(s) on which to automatically add page-breaks. One or more of `'avoid-all'`, `'css'`, and `'legacy'`. |

|before    |string or array |`[]`                |CSS selectors for which to add page-breaks before each element. Can be a specific element with an ID (`'#myID'`), all elements of a type (e.g. `'img'`), all of a class (`'.myClass'`), or even `'*'` to match every element. |

|after     |string or array |`[]`                |Like 'before', but adds a page-break immediately after the element. |

|avoid     |string or array |`[]`                |Like 'before', but avoids page-breaks on these elements. You can enable this feature on every element using the 'avoid-all' mode. |



#### Page-break modes



| Mode      | Description |

|-----------|-------------|

| avoid-all | Automatically adds page-breaks to avoid splitting any elements across pages. |

| css       | Adds page-breaks according to the CSS `break-before`, `break-after`, and `break-inside` properties. Only recognizes `always/left/right` for before/after, and `avoid` for inside. |

| legacy    | Adds page-breaks after elements with class `html2pdf__page-break`. This feature may be removed in the future. |



#### Example usage



```js

// Avoid page-breaks on all elements, and add one before #page2el.

html2pdf().set({

  pagebreak: { mode: 'avoid-all', before: '#page2el' }

});



// Enable all 'modes', with no explicit elements.

html2pdf().set({

  pagebreak: { mode: ['avoid-all', 'css', 'legacy'] }

});



// No modes, only explicit elements.

html2pdf().set({

  pagebreak: { before: '.beforeClass', after: ['#after1', '#after2'], avoid: 'img' }

});

```



### Image type and quality



You may customize the image type and quality exported from the canvas by setting the `image` option. This must be an object with the following fields:



|Name        |Type            |Default                       |Description                                                                                  |

|------------|----------------|------------------------------|---------------------------------------------------------------------------------------------|

|type        |string          |'jpeg'                        |The image type. HTMLCanvasElement only supports 'png', 'jpeg', and 'webp' (on Chrome).       |

|quality     |number          |0.95                          |The image quality, from 0 to 1. This setting is only used for jpeg/webp (not png).           |



These options are limited to the available settings for [HTMLCanvasElement.toDataURL()](https://developer.mozilla.org/en-US/docs/Web/API/HTMLCanvasElement/toDataURL), which ignores quality settings for 'png' images. To enable png image compression, try using the [canvas-png-compression shim](https://github.com/ShyykoSerhiy/canvas-png-compression), which should be an in-place solution to enable png compression via the `quality` option.



## Progress tracking



The Worker object returned by `html2pdf()` has a built-in progress-tracking mechanism. It will be updated to allow a progress callback that will be called with each update, however it is currently a work-in-progress.



## Dependencies



html2pdf.js depends on the external packages [html2canvas](https://github.com/niklasvh/html2canvas), [jsPDF](https://github.com/MrRio/jsPDF), and [es6-promise](https://github.com/stefanpenner/es6-promise). These dependencies are automatically loaded when using NPM or the bundled package.



If using the unbundled `dist/html2pdf.min.js` (or its un-minified version), you must also include each dependency. Order is important, otherwise html2canvas will be overridden by jsPDF's own internal implementation:



```html



```



## Contributing



### Issues



When submitting an issue, please provide reproducible code that highlights the issue, preferably by creating a fork of [this template jsFiddle](https://jsfiddle.net/u6o6ne41/) (which has html2pdf.js already loaded). Remember that html2pdf.js uses [html2canvas](https://github.com/niklasvh/html2canvas) and [jsPDF](https://github.com/MrRio/jsPDF) as dependencies, so it's a good idea to check each of those repositories' issue trackers to see if your problem has already been addressed.



#### Known issues



1. **Rendering:** The rendering engine html2canvas isn't perfect (though it's pretty good!). If html2canvas isn't rendering your content correctly, I can't fix it.

    - You can test this with something like [this fiddle](https://jsfiddle.net/eKoopmans/z1rupL4c/), to see if there's a problem in the canvas creation itself.



2. **Node cloning (CSS etc):** The way html2pdf.js clones your content before sending to html2canvas is buggy. A fix is currently being developed - try out:

    - direct file: Go to [html2pdf.js/bugfix/clone-nodes-BUILD](/eKoopmans/html2pdf.js/tree/bugfix/clone-nodes-BUILD) and replace the files in your project with the relevant files (e.g. `dist/html2pdf.bundle.js`)

    - npm: `npm install eKoopmans/html2pdf.js#bugfix/clone-nodes-BUILD`

    - Related project: [Bugfix: Cloned nodes](https://github.com/eKoopmans/html2pdf.js/projects/9)



3. **Resizing:** Currently, html2pdf.js resizes the root element to fit onto a PDF page (causing internal content to "reflow").

    - This is often desired behaviour, but not always.

    - There are plans to add alternate behaviour (e.g. "shrink-to-page"), but nothing that's ready to test yet.

    - Related project: [Feature: Single-page PDFs](https://github.com/eKoopmans/html2pdf.js/projects/1)



4. **Rendered as image:** html2pdf.js renders all content into an image, then places that image into a PDF.

    - This means text is *not selectable or searchable*, and causes large file sizes.

    - This is currently unavoidable, however recent improvements in jsPDF mean that it may soon be possible to render straight into vector graphics.

    - Related project: [Feature: New renderer](https://github.com/eKoopmans/html2pdf.js/projects/4)



5. **Promise clashes:** html2pdf.js relies on specific Promise behaviour, and can fail when used with custom Promise libraries.

    - In the next release, Promises will be sandboxed in html2pdf.js to remove this issue.

    - Related project: [Bugfix: Sandboxed promises](https://github.com/eKoopmans/html2pdf.js/projects/11)



6. **Maximum size:** HTML5 canvases have a [maximum height/width](https://stackoverflow.com/a/11585939/4080966). Anything larger will fail to render.

    - This is a limitation of HTML5 itself, and results in large PDFs rendering completely blank in html2pdf.js.

    - The jsPDF canvas renderer (mentioned in Known Issue #4) may be able to fix this issue!

    - Related project: [Bugfix: Maximum canvas size](https://github.com/eKoopmans/html2pdf.js/projects/5)



### Tests



html2pdf.js is currently sorely lacking in unit tests. Any contributions or suggestions of automated (or manual) tests are welcome. This is high on the to-do list for this project.



### Pull requests



If you want to create a new feature or bugfix, please feel free to fork and submit a pull request! Create a fork, branch off of `master`, and make changes to the `/src/` files (rather than directly to `/dist/`). You can test your changes by rebuilding with `npm run build`.



## Credits



[Erik Koopmans](https://github.com/eKoopmans)



#### Contributors



- [@WilcoBreedt](https://github.com/WilcoBreedt)

- [@Ranger1230](https://github.com/Ranger1230)



#### Special thanks



- [Sauce Labs](https://saucelabs.com/) for unit testing.



## License



[The MIT License](http://opensource.org/licenses/MIT)



Copyright (c) 2017-2019 Erik Koopmans <[http://www.erik-koopmans.com/](http://www.erik-koopmans.com/)>