# html5parser > A super fast & tiny HTML5 parser Latest version **3.0.0** (published 2026-05-15) · MIT license · 0 weekly downloads ## Install ```sh npm install html5parser pnpm add html5parser yarn add html5parser bun add html5parser ``` ## Health **Score 70/100 (B)** — status: active. Positive: has types; esm support; no vulnerabilities; has provenance; high maintenance score; high quality score. Warnings: low downloads. ## Facts | | | |---|---| | Version | 3.0.0 | | Published | 2026-05-15 | | First published | 2017-08-18 | | Weekly downloads | 0 | | License | MIT | | TypeScript types | bundled | | Module format | ESM + CommonJS | | Dependencies | 0 | | Unpacked size | 267.4 KB | | Known vulnerabilities | 0 | | Install scripts | no | | Provenance | attested (GitHub Actions) | | GitHub stars | 182 | | Author | acrazing | | Maintainers | acrazing | | Keywords | html5, parser, ast, attributes | ## Links - npm: https://www.npmjs.com/package/html5parser - Repository: https://github.com/acrazing/html5parser - Homepage: https://github.com/acrazing/html5parser#readme - Issues: https://github.com/acrazing/html5parser/issues - npm.io page: https://npm.io/package/html5parser ## Alternatives - [babylon](https://npm.io/package/babylon.md) — 5.1M weekly downloads - [csscolorparser](https://npm.io/package/csscolorparser.md) — 3.7M weekly downloads - [expr-eval-fork](https://npm.io/package/expr-eval-fork.md) — 1.5M weekly downloads - [@leeoniya/ufuzzy](https://npm.io/package/@leeoniya/ufuzzy.md) — 247.7K weekly downloads - [xml-parser](https://npm.io/package/xml-parser.md) — 78.4K weekly downloads ## Recent versions - 3.0.0 (latest) — 2026-05-15 - 3.0.0-beta.1 (beta) — 2026-05-15 - 2.0.0-next (next) — 2020-11-11 - 3.0.0-beta.0 — 2026-05-15 - 2.0.2 — 2021-05-11 - 2.0.1 — 2021-04-16 - 2.0.0 — 2020-11-11 - 1.2.1 — 2020-10-19 - 1.2.0 — 2020-09-09 - 1.1.2 — 2020-02-12 - 1.1.1 — 2020-02-06 - 1.1.0 — 2019-07-31 - 1.0.0 — 2019-07-24 - 0.3.0 — 2017-08-24 - 0.2.0 — 2017-08-21 - … 3 more at https://npm.io/package/html5parser/versions ## README # html5parser `html5parser` is a super fast and tiny **HTML5** parser. ## Highlights - **[Fast](#benchmark)**: maybe the fastest one you can find on GitHub. - **Tiny**: the fully packaged bundle size is less than `5kb`. - **Cross platform**: works in the modern browsers and Node.js. - **[HTML5 only](#warnings)**: any thing not in the specification will be ignored. - **Accurate**: every token could be located in source file. ## Table of Contents - [Installation](#installation) - [Quick start](#quick-start) - [API Reference](#api-reference) - Core - [tokenize()](#tokenizeinput) - [parse()](#parseinput) - [stringify()](#stringifyast) - Utilities - [walk()](#walkast-options) - [Warnings](#warnings) - [Benchmark](#benchmark) ## Installation 1. Package manager ```bash npm i -S html5parser # or var yarn yarn add html5parser ``` 2. CDN ```html ``` ## Quick start [![Edit html5parser - quick start](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/keen-wind-2mpwr?fontsize=14&hidenavigation=1&theme=dark) ```typescript jsx import { parse, walk, SyntaxKind } from 'html5parser'; const ast = parse('Hello html5parser!'); walk(ast, { enter: (node) => { if (node.type === SyntaxKind.Tag && node.name === 'title' && Array.isArray(node.body)) { const text = node.body[0]; if (text.type !== SyntaxKind.Text) { return; } const div = document.createElement('div'); div.innerHTML = `The title of the input is ${text.value}`; document.body.appendChild(div); } }, }); ``` ## API Reference ### tokenize(input) Low level API to parse string to tokens: ```typescript jsx function tokenize(input: string): IToken[]; ``` - `IToken` ```typescript jsx interface IToken { start: number; end: number; value: string; type: TokenKind; } ``` - `TokenKind` ```typescript jsx const enum TokenKind { Literal, OpenTag, // trim leading '<' OpenTagEnd, // trim tailing '>', only could be '/' or '' CloseTag, // trim leading '' Whitespace, // the whitespace between attributes AttrValueEq, AttrValueNq, AttrValueSq, AttrValueDq, } ``` ### parse(input) Core API to parse string to AST: ```typescript jsx function parse(input: string, options?: ParseOptions): INode[]; ``` - `ParseOptions` ```typescript jsx interface ParseOptions { // create tag's attributes map // if true, will set ITag.attributeMap property // as a `Record` setAttributeMap: boolean; } ``` - `INode` ```typescript jsx export type INode = IText | ITag; ``` - `ITag` ```typescript jsx export interface ITag extends IBaseNode { type: SyntaxKind.Tag; // original open tag,
open: IText; // lower case tag name, div name: string; // original case tag name, Div rawName: string; attributes: IAttribute[]; // the attribute map, if `options.setAttributeMap` is `true` // this will be a Record, key is the attribute name literal, // value is the attribute self. attributeMap: Record | undefined; body: | Array // with close tag | undefined // self closed | null; // EOF before open tag end // original close tag,
close: | IText // with close tag | undefined // self closed | null; // EOF before end or without close tag } ``` - `IAttribute` ```typescript jsx export interface IAttribute extends IBaseNode { name: IText; value: IAttributeValue | undefined; } ``` - `IAttributeValue` ```typescript jsx export interface IAttributeValue extends IBaseNode { value: string; quote: "'" | '"' | undefined; } ``` - `IText` ```typescript jsx export interface IText extends IBaseNode { type: SyntaxKind.Text; value: string; } ``` - `IBaseNode` ```typescript jsx export interface IBaseNode { start: number; end: number; } ``` - `SyntaxKind` ```typescript jsx export enum SyntaxKind { Text = 'Text', Tag = 'Tag', } ``` ### stringify(ast) Serialize AST nodes back to HTML: ```typescript jsx function stringify(ast: INode | INode[]): string; ``` `stringify` is a serializer, not a sanitizer. Text and attribute values are emitted as-is, so escape user-created values before adding them to the AST. Opening tag whitespace is normalized, and attributes are serialized from `ITag.attributes` in order. `ITag.attributeMap` is only a lookup view. Use `setAttribute` and `removeAttribute` to update a tag's serialized attributes: ```typescript jsx function setAttribute(tag: ITag, name: string, value?: string): void; function removeAttribute(tag: ITag, name: string): void; ``` ### walk(ast, options) Visit all the nodes of the AST with specified callbacks: ```typescript jsx function walk(ast: INode[], options: WalkOptions): void; ``` - `IWalkOptions` ```typescript jsx export interface IWalkOptions { enter?(node: INode, parent: INode | void, index: number): void; leave?(node: INode, parent: INode | void, index: number): void; } ``` ## Warnings This is use for HTML5, that means: 1. All tags like ``, `` (except for ``, case insensitive) is treated as `Comment`, that means `CDATASection` is treated as comment. 2. Special tag names: - `"!doctype"` (case insensitive), the doctype declaration - `"!"`: short comment - `"!--"`: normal comment - `""`(empty string): short comment, for ``, the leading `?` is treated as comment content ## Benchmark Thanks for [htmlparser-benchmark](https://github.com/AndreasMadsen/htmlparser-benchmark), I created a pull request at [pulls/7](https://github.com/AndreasMadsen/htmlparser-benchmark/pull/7/files), and its result on my MacBook Pro is: ```bash $ npm test > htmlparser-benchmark@1.1.3 test ~/htmlparser-benchmark > node execute.js gumbo-parser failed (exit code 1) high5 failed (exit code 1) html-parser : 28.6524 ms/file ± 21.4282 html5 : 130.423 ms/file ± 161.478 html5parser : 2.37975 ms/file ± 3.30717 htmlparser : 16.6576 ms/file ± 109.840 htmlparser2-dom : 3.45602 ms/file ± 5.05830 htmlparser2 : 2.61135 ms/file ± 4.33535 hubbub failed (exit code 1) libxmljs failed (exit code 1) neutron-html5parser: 2.89331 ms/file ± 2.94316 parse5 failed (exit code 1) sax : 10.2110 ms/file ± 13.5204 ``` ## License ``` The MIT License (MIT) Copyright (c) 2020 acrazing Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. ``` --- _Source: https://npm.io/package/html5parser · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._