ObsoHTML, the Obsolete HTML Checker

ObsoHTML is a Node.js tool designed to scan HTML, PHP, Nunjucks, Twig, JavaScript, and TypeScript files for obsolete and proprietary HTML elements and attributes. It helps you identify and update deprecated HTML code to be sure to use web standards.

ObsoHTML has inherent limitations and may not find all obsolete elements and attributes. If you run into a problem, please file an issue.

Usage

1. CLI

Installation

Consider using ObsoHTML via npx:

npx obsohtml

Execution

ObsoHTML accepts a folder or file path as an argument. The path can be either absolute or relative; when it’s omitted, ObsoHTML checks the current directory.

ObsoHTML can be run in “verbose” mode by appending -v or --verbose to the command. This will show information about files and directories that were skipped.

Example Commands

Check the current directory:

npx obsohtml

Specify a folder using an absolute path:

npx obsohtml /path/to/folder

Specify a folder using a relative path:

npx obsohtml ../path/to/folder

Specify a single file:

npx obsohtml src/index.html

2. Programmatic Use

Install ObsoHTML in your project, e.g., via npm i -D obsohtml, then import and use what you need:

import { checkMarkup, locateMarkup, obsoleteElements, obsoleteAttributes } from 'obsohtml';

const { elements, attributes } = checkMarkup('<center>Hello</center>');
// elements: ['center']
// attributes: []

const located = locateMarkup('<center>\n<img align=left></center>');
// elements: [{ name: 'center', line: 1, col: 1 }]
// attributes: [{ name: 'align', line: 2, col: 6 }]

checkMarkup(html)

Checks an HTML string for obsolete and proprietary elements and attributes.

• Parameter: html (string)—the HTML content to check
• Returns: { elements: string[], attributes: string[] }—arrays of found obsolete element and attribute names

locateMarkup(html)

Locates every obsolete and proprietary element and attribute in an HTML string.

• Parameter: html (string)—the HTML content to check
• Returns: { elements: Occurrence[], attributes: Occurrence[] }—every occurrence as { name, line, col }, sorted by position (lines and columns start at 1; for elements, the column points to <, for attributes to the attribute name)

obsoleteElements

Array of obsolete or proprietary HTML element names checked by ObsoHTML.

obsoleteAttributes

Array of obsolete or proprietary HTML attribute names checked by ObsoHTML.

Output

The script will output messages to the console indicating any obsolete elements or attributes found in the scanned files, one per occurrence, along with where they were detected (path:line:col).

The script exits with code 1 if any obsolete HTML is found, and 0 if none is found, making it suitable for use in CI pipelines.

Background

This started as an experiment, in which I used AI to produce this little HTML quality helper, its tests, and its documentation. While it’s pretty straightforward, I’m sure to have missed something. Please file an issue or contact me directly if you spot a problem or have a suggestion.

Acknowledgments

Thanks to @mattbrundage, @FabianBeiner, and @AndrewMac for helping to make ObsoHTML better!

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You might like some of my other work:

• Optimization tools: hihtml · HTML Minifier Next · ObsoHTML · CSS Dedup · Image Guard · Compressor.js Next · .htaccess Punk
• Defense tools: IA Defensa
• Resources for quality web development: Articles · Books (including On Web Development) · News · Terminology