1# htmlparser2
2
3[![NPM version](http://img.shields.io/npm/v/htmlparser2.svg?style=flat)](https://npmjs.org/package/htmlparser2)
4[![Downloads](https://img.shields.io/npm/dm/htmlparser2.svg?style=flat)](https://npmjs.org/package/htmlparser2)
5[![Build Status](https://img.shields.io/github/workflow/status/fb55/htmlparser2/Node.js%20Test?label=tests&style=flat)](https://github.com/fb55/htmlparser2/actions?query=workflow%3A%22Node.js+Test%22)
6[![Coverage](http://img.shields.io/coveralls/fb55/htmlparser2.svg?style=flat)](https://coveralls.io/r/fb55/htmlparser2)
7
8The fast & forgiving HTML/XML parser.
9
10## Installation
11
12    npm install htmlparser2
13
14A live demo of `htmlparser2` is available [here](https://astexplorer.net/#/2AmVrGuGVJ).
15
16## Ecosystem
17
18| Name                                                          | Description                                             |
19| ------------------------------------------------------------- | ------------------------------------------------------- |
20| [htmlparser2](https://github.com/fb55/htmlparser2)            | Fast & forgiving HTML/XML parser                        |
21| [domhandler](https://github.com/fb55/domhandler)              | Handler for htmlparser2 that turns documents into a DOM |
22| [domutils](https://github.com/fb55/domutils)                  | Utilities for working with domhandler's DOM             |
23| [css-select](https://github.com/fb55/css-select)              | CSS selector engine, compatible with domhandler's DOM   |
24| [cheerio](https://github.com/cheeriojs/cheerio)               | The jQuery API for domhandler's DOM                     |
25| [dom-serializer](https://github.com/cheeriojs/dom-serializer) | Serializer for domhandler's DOM                         |
26
27## Usage
28
29`htmlparser2` itself provides a callback interface that allows consumption of documents with minimal allocations.
30For a more ergonomic experience, read [Getting a DOM](#getting-a-dom) below.
31
32```javascript
33const htmlparser2 = require("htmlparser2");
34const parser = new htmlparser2.Parser({
35    onopentag(name, attributes) {
36        /*
37         * This fires when a new tag is opened.
38         *
39         * If you don't need an aggregated `attributes` object,
40         * have a look at the `onopentagname` and `onattribute` events.
41         */
42        if (name === "script" && attributes.type === "text/javascript") {
43            console.log("JS! Hooray!");
44        }
45    },
46    ontext(text) {
47        /*
48         * Fires whenever a section of text was processed.
49         *
50         * Note that this can fire at any point within text and you might
51         * have to stich together multiple pieces.
52         */
53        console.log("-->", text);
54    },
55    onclosetag(tagname) {
56        /*
57         * Fires when a tag is closed.
58         *
59         * You can rely on this event only firing when you have received an
60         * equivalent opening tag before. Closing tags without corresponding
61         * opening tags will be ignored.
62         */
63        if (tagname === "script") {
64            console.log("That's it?!");
65        }
66    },
67});
68parser.write(
69    "Xyz <script type='text/javascript'>const foo = '<<bar>>';</ script>"
70);
71parser.end();
72```
73
74Output (with multiple text events combined):
75
76```
77--> Xyz
78JS! Hooray!
79--> const foo = '<<bar>>';
80That's it?!
81```
82
83This example only shows three of the possible events.
84Read more about the parser, its events and options in the [wiki](https://github.com/fb55/htmlparser2/wiki/Parser-options).
85
86### Usage with streams
87
88While the `Parser` interface closely resembles Node.js streams, it's not a 100% match.
89Use the `WritableStream` interface to process a streaming input:
90
91```javascript
92const { WritableStream } = require("htmlparser2/lib/WritableStream");
93const parserStream = new WritableStream({
94    ontext(text) {
95        console.log("Streaming:", text);
96    },
97});
98
99const htmlStream = fs.createReadStream("./my-file.html");
100htmlStream.pipe(parserStream).on("finish", () => console.log("done"));
101```
102
103## Getting a DOM
104
105The `DomHandler` produces a DOM (document object model) that can be manipulated using the [`DomUtils`](https://github.com/fb55/DomUtils) helper.
106
107```js
108const htmlparser2 = require("htmlparser2");
109
110const dom = htmlparser2.parseDocument();
111```
112
113The `DomHandler`, while still bundled with this module, was moved to its [own module](https://github.com/fb55/domhandler).
114Have a look at that for further information.
115
116## Parsing RSS/RDF/Atom Feeds
117
118```javascript
119const feed = htmlparser2.parseFeed(content, options);
120```
121
122Note: While the provided feed handler works for most feeds,
123you might want to use [danmactough/node-feedparser](https://github.com/danmactough/node-feedparser), which is much better tested and actively maintained.
124
125## Performance
126
127After having some artificial benchmarks for some time, **@AndreasMadsen** published his [`htmlparser-benchmark`](https://github.com/AndreasMadsen/htmlparser-benchmark), which benchmarks HTML parses based on real-world websites.
128
129At the time of writing, the latest versions of all supported parsers show the following performance characteristics on [Travis CI](https://travis-ci.org/AndreasMadsen/htmlparser-benchmark/builds/10805007) (please note that Travis doesn't guarantee equal conditions for all tests):
130
131```
132gumbo-parser   : 34.9208 ms/file ± 21.4238
133html-parser    : 24.8224 ms/file ± 15.8703
134html5          : 419.597 ms/file ± 264.265
135htmlparser     : 60.0722 ms/file ± 384.844
136htmlparser2-dom: 12.0749 ms/file ± 6.49474
137htmlparser2    : 7.49130 ms/file ± 5.74368
138hubbub         : 30.4980 ms/file ± 16.4682
139libxmljs       : 14.1338 ms/file ± 18.6541
140parse5         : 22.0439 ms/file ± 15.3743
141sax            : 49.6513 ms/file ± 26.6032
142```
143
144## How does this module differ from [node-htmlparser](https://github.com/tautologistics/node-htmlparser)?
145
146This module started as a fork of the `htmlparser` module.
147The main difference is that `htmlparser2` is intended to be used only with node (it runs on other platforms using [browserify](https://github.com/substack/node-browserify)).
148`htmlparser2` was rewritten multiple times and, while it maintains an API that's compatible with `htmlparser` in most cases, the projects don't share any code anymore.
149
150The parser now provides a callback interface inspired by [sax.js](https://github.com/isaacs/sax-js) (originally targeted at [readabilitySAX](https://github.com/fb55/readabilitysax)).
151As a result, old handlers won't work anymore.
152
153The `DefaultHandler` and the `RssHandler` were renamed to clarify their purpose (to `DomHandler` and `FeedHandler`). The old names are still available when requiring `htmlparser2`, your code should work as expected.
154
155## Security contact information
156
157To report a security vulnerability, please use the [Tidelift security contact](https://tidelift.com/security).
158Tidelift will coordinate the fix and disclosure.
159
160## `htmlparser2` for enterprise
161
162Available as part of the Tidelift Subscription
163
164The maintainers of `htmlparser2` and thousands of other packages are working with Tidelift to deliver commercial support and maintenance for the open source dependencies you use to build your applications. Save time, reduce risk, and improve code health, while paying the maintainers of the exact dependencies you use. [Learn more.](https://tidelift.com/subscription/pkg/npm-htmlparser2?utm_source=npm-htmlparser2&utm_medium=referral&utm_campaign=enterprise&utm_term=repo)
165