html5lib in Pure Dart

This is a pure Dart html5 parser. It's a port of html5lib from Python. Since it's 100% Dart you can use it safely from a script or server side app.

Eventually the parse tree API will be compatible with dart:html, so the same code will work on the client or the server.


Add this to your pubspec.yaml (or create it):

  html5lib: any

Then run the Pub Package Manager (comes with the Dart SDK):

pub install


Parsing HTML is easy!

import 'package:html5lib/parser.dart' show parse;
import 'package:html5lib/dom.dart';

main() {
  var document = parse(
      '<body>Hello world! <a href="">HTML5 rocks!');

You can pass a String or list of bytes to parse. There's also parseFragment for parsing a document fragment, and HtmlParser if you want more low level control.


You can upgrade the library with:

pub update

Disclaimer: the APIs are not finished. Updating may break your code. If that happens, you can check the commit log, to figure out what the change was.

If you want to avoid breakage, you can also put the version constraint in your pubspec.yaml in place of the word any.

Implementation Status

Right now the tokenizer, html5parser, and simpletree are working.

These files from the html5lib directory still need to be ported:

  • filters/*
  • serializer/*
  • some of treebuilders/*
  • treewalkers/*
  • the tests corresponding to the above files

Running Tests

All tests should be passing.

# Make sure dependencies are installed
pub install

# Run command line tests
#export DART_SDK=path/to/dart/sdk


A simple tree API that results from parsing html. Intended to be compatible with dart:html, but right now it resembles the classic JS DOM.
This library contains extra APIs that aren't in the DOM, but are useful when interacting with the parse tree.
This library has a parser for HTML5 documents, that lets you parse HTML easily from a script or server side application: [...]
This library adds dart:io support to the HTML5 parser. Call initDartIOSupport before calling the parse methods and they will accept a RandomAccessFile as input, in addition to the other input types.