Back to Skills

creating-bookmarklets

majiayu000
Updated Today
58
9
58
View on GitHub
Metadesign

About

This skill generates browser bookmarklets as executable JavaScript code with strict formatting requirements. It automatically wraps code in an IIFE, uses only block comments for compatibility, and prepends the `javascript:` protocol. Use it when developers need to create or debug bookmarklets for browser automation or utilities.

Quick Install

Claude Code

Recommended
Plugin CommandRecommended
/plugin add https://github.com/majiayu000/claude-skill-registry
Git CloneAlternative
git clone https://github.com/majiayu000/claude-skill-registry.git ~/.claude/skills/creating-bookmarklets

Copy and paste this command in Claude Code to install this skill

Documentation

Bookmarklet Creation

Critical Requirements

Comment Style - ABSOLUTE

Use ONLY /* */ comments. NEVER use // comments.

Bookmark execution contexts fail with // style. Every comment must use block format.

/* ✓ Correct */
const x = 5; /* inline */

/* ✗ Wrong - breaks bookmarklets */
// const x = 5;
const y = 10; // inline

IIFE Wrapper

All bookmarklets must wrap in IIFE:

(function() {
  /* bookmarklet code */
})();

Protocol Prefix

All delivered bookmarklets must begin with javascript: protocol:

javascript:(function() {
  /* bookmarklet code */
})();

This makes the code immediately usable without requiring manual modification during installation.

Workflow

1. Generate Pretty-Printed Code

Create readable source with:

  • 2-space indentation
  • Descriptive variable names
  • Block comments for key sections
  • Logical organization
  • Prepend javascript: protocol to the code

This version with javascript: prefix gets stored in GitHub and shown to users, making it ready for installation without manual modification.

2. Provide Installation

Default approach - reference installer:

Install: https://austegard.com/web-utilities/bookmarklet-installer.html

Installer handles:

  • Minification with Terser
  • URL encoding
  • Draggable link generation
  • GitHub repo integration

Alternative - generate link programmatically: Use Terser.js to create installable link if requested:

async function createBookmarkletLink(code, title) {
  const minified = await Terser.minify(code);
  const encoded = encodeURIComponent(minified.code).replace(/'/g, "%27");
  return `<a href="javascript:${encoded}">${title}</a>`;
}

Requires: <script src="https://cdn.jsdelivr.net/npm/terser/dist/bundle.min.js"></script>

3. Deliverables

Always provide:

  1. Pretty-printed source code with javascript: protocol prepended
  2. Installation method (installer link or generated link)
  3. Brief description of functionality
  4. Usage instructions

The code should be delivered in a format ready for direct use - users should be able to copy the entire code block (including javascript:) without modification.

Code Standards

Error Handling

(function() {
  try {
    /* main logic */
  } catch (error) {
    console.error('Bookmarklet error:', error);
    alert('Operation failed: ' + error.message);
  }
})();

Console Logging

Include debug traces by default:

console.log('Bookmarklet: Starting');
/* operations */
console.log('Bookmarklet: Complete');

User Feedback

/* Success */
alert('✓ Content copied to clipboard');

/* Error */
alert('✗ Failed to access clipboard');

Common Patterns

DOM Manipulation

(function() {
  const element = document.querySelector('.target');
  if (!element) {
    alert('Element not found');
    return;
  }
  /* manipulate element */
})();

Data Extraction

(function() {
  const data = Array.from(document.querySelectorAll('.item'))
    .map(item => ({
      title: item.querySelector('.title')?.textContent.trim(),
      value: item.querySelector('.value')?.textContent.trim()
    }));
  
  console.log('Extracted:', data);
})();

Clipboard Operations

(function() {
  const text = 'content to copy';
  navigator.clipboard.writeText(text)
    .then(() => alert('✓ Copied'))
    .catch(err => {
      console.error('Clipboard error:', err);
      alert('✗ Copy failed');
    });
})();

Dynamic Library Loading

(function() {
  if (typeof someLibrary === 'undefined') {
    const script = document.createElement('script');
    script.src = 'https://cdn.example.com/library.js';
    script.onload = function() {
      /* proceed with logic */
    };
    document.head.appendChild(script);
  }
})();

Browser Compatibility

Provide fallbacks for unsupported features:

if (!navigator.clipboard) {
  alert('Clipboard API not supported');
  return;
}

Constraints

Cannot use:

  • External files (CSS, images) without embedding
  • Build tools or preprocessing
  • // style comments

Can use:

  • Fetch API
  • localStorage/sessionStorage
  • Modern browser APIs
  • CDN libraries (loaded dynamically)

Testing

Before delivering:

  1. Verify no // comments exist
  2. Test in browser console wrapped in IIFE
  3. Check error handling with missing DOM elements
  4. Verify user feedback for all paths

Example Output

javascript:(function() {
  /* Pretty-printed bookmarklet code */
})();

Install: https://austegard.com/web-utilities/bookmarklet-installer.html

Extracts all links from current page and copies to clipboard as markdown list. Works on any webpage.

GitHub Storage

User repository: https://github.com/oaustegard/bookmarklets

Pretty-printed format matches storage requirements. Installer loads directly from this repo.

GitHub Repository

majiayu000/claude-skill-registry
Path: skills/creating-bookmarklets

Related Skills

content-collections

Meta

This skill provides a production-tested setup for Content Collections, a TypeScript-first tool that transforms Markdown/MDX files into type-safe data collections with Zod validation. Use it when building blogs, documentation sites, or content-heavy Vite + React applications to ensure type safety and automatic content validation. It covers everything from Vite plugin configuration and MDX compilation to deployment optimization and schema validation.

View skill

creating-opencode-plugins

Meta

This skill provides the structure and API specifications for creating OpenCode plugins that hook into 25+ event types like commands, files, and LSP operations. It offers implementation patterns for JavaScript/TypeScript modules that intercept and extend the AI assistant's lifecycle. Use it when you need to build event-driven plugins for monitoring, custom handling, or extending OpenCode's capabilities.

View skill

langchain

Meta

LangChain is a framework for building LLM applications using agents, chains, and RAG pipelines. It supports multiple LLM providers, offers 500+ integrations, and includes features like tool calling and memory management. Use it for rapid prototyping and deploying production systems like chatbots, autonomous agents, and question-answering services.

View skill

Algorithmic Art Generation

Meta

This skill helps developers create algorithmic art using p5.js, focusing on generative art, computational aesthetics, and interactive visualizations. It automatically activates for topics like "generative art" or "p5.js visualization" and guides you through creating unique algorithms with features like seeded randomness, flow fields, and particle systems. Use it when you need to build reproducible, code-driven artistic patterns.

View skill