html2pdf.js converts any webpage or element into a printable PDF entirely client-side using html2canvas and jsPDF.
⚠️ 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).
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.
Note: Read about dependences 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:
<scriptsrc="html2pdf.bundle.min.js"></script>
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:
Open your browser's console (instructions for different browsers here).
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:
varworker=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:
// This will implicitly create the canvas and PDF objects before saving.varworker=html2pdf().from(element).save();
Workflow
The basic workflow of html2pdf.js tasks (enforced by the prereq system) is:
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 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 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 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:
varelement=document.getElementById('element-to-print');varopt={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 below.
If enabled, PDF hyperlinks are automatically added ontop of all anchor tags.
html2canvas
object
{ }
Configuration options sent directly to html2canvas (see here for usage).
jsPDF
object
{ }
Configuration options sent directly to jsPDF (see here 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, break-after, and 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
// 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(), which ignores quality settings for 'png' images. To enable png image compression, try using the canvas-png-compression shim, 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, jsPDF, and 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:
When submitting an issue, please provide reproducible code that highlights the issue, preferably by creating a fork of this template jsFiddle (which has html2pdf.js already loaded). Remember that html2pdf.js uses html2canvas and 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
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, to see if there's a problem in the canvas creation itself.
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 and replace the files in your project with the relevant files (e.g. dist/html2pdf.bundle.js)
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.
请发表评论