Browser App Creator

Browser App Creator

Purpose

Creates production-ready single-file web applications that work offline with zero setup. Perfect for quick tools, dashboards, trackers, and prototypes.

For ADHD users: Large buttons (60px+), auto-save everything, visual feedback, zero configuration. For SDAM users: All data persists in localStorage with timestamps. For all users: Download and use immediately - no server, no build step, no dependencies.

Activation Triggers

• User says: "create app", "build tool", "make dashboard", "create tracker"
• Requests for: habit tracker, todo list, timer, calculator, form, visualization
• Any request for a browser-based interface or tool

Core Workflow

1. Understand Requirements

Ask clarifying questions only if absolutely necessary:

{
  app_type: "dashboard|tracker|form|tool|visualization",
  primary_function: "What does the app do?",
  data_to_track: ["What data needs to be stored?"],
  key_actions: ["What can users do?"],
  visual_requirements: "Any specific layout needs?"
}

2. Generate Single-File App

Template structure:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>{App Name}</​title>
  <style>
    /​* ADHD-Optimized Styles */
  </​style>
</​head>
<body>
  <!-- App UI -->
  <script>
    // App Logic + localStorage
  </​script>
</​body>
</​html>

3. ADHD Optimization Requirements

Required UI elements:

• ✅ Buttons: Minimum 60px height, high contrast
• ✅ Dark mode: Default theme (can toggle)
• ✅ Auto-save: Every action saves to localStorage
• ✅ Visual feedback: Success/​error messages
• ✅ Mobile responsive: Works on all screen sizes
• ✅ Large touch targets: 44px minimum for mobile

CSS Requirements:

/​* ADHD-Optimized Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: #1a1a1a;
  color: #e0e0e0;
  padding: 20px;
  max-width: 1200px;
  margin: 0 auto;
}

button {
  min-height: 60px;
  padding: 15px 30px;
  font-size: 18px;
  font-weight: 600;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s ease;
  background: #4a9eff;
  color: white;
}

button:hover {
  background: #357abd;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(74, 158, 255, 0.4);
}

button:active {
  transform: translateY(0);
}

input, textarea, select {
  min-height: 50px;
  padding: 12px 15px;
  font-size: 16px;
  border: 2px solid #333;
  border-radius: 6px;
  background: #2a2a2a;
  color: #e0e0e0;
  width: 100%;
}

input:focus, textarea:focus, select:focus {
  outline: none;
  border-color: #4a9eff;
  box-shadow: 0 0 0 3px rgba(74, 158, 255, 0.2);
}

4. localStorage Pattern

Always include:

// localStorage Manager
const Storage = {
  key: 'app-name-data',

  save(data) {
    try {
      localStorage.setItem(this.key, JSON.stringify({
        ...data,
        lastUpdated: new Date().toISOString()
      }));
      this.showFeedback('✅ Saved!');
    } catch (error) {
      this.showFeedback('❌ Save failed', true);
      console.error('Save error:', error);
    }
  },

  load() {
    try {
      const data = localStorage.getItem(this.key);
      return data ? JSON.parse(data) : this.getDefaults();
    } catch (error) {
      console.error('Load error:', error);
      return this.getDefaults();
    }
  },

  getDefaults() {
    return {
      items: [],
      settings: {},
      created: new Date().toISOString()
    };
  },

  showFeedback(message, isError = false) {
    const feedback = document.createElement('div');
    feedback.textContent = message;
    feedback.style.cssText = `
      position: fixed;
      top: 20px;
      right: 20px;
      padding: 15px 25px;
      background: ${isError ? '#ff4444' : '#44ff88'};
      color: #000;
      border-radius: 8px;
      font-weight: 600;
      box-shadow: 0 4px 12px rgba(0,0,0,0.3);
      z-index: 1000;
      animation: slideIn 0.3s ease;
    `;
    document.body.appendChild(feedback);
    setTimeout(() => feedback.remove(), 2000);
  }
};

// Auto-save on any change
function autoSave(data) {
  Storage.save(data);
}

// Load on page load
let appData = Storage.load();

5. App Templates

See templates.md for complete examples of:

• Dashboard: Metrics, charts, status indicators
• Tracker: Habits, tasks, progress
• Form: Data entry, validation, submission
• Tool: Calculators, converters, utilities
• Visualization: Charts, graphs, timelines

6. Deliver the App

Format:

✅ **{App Name}** complete!

**Features**:
- {Feature 1}
- {Feature 2}
- {Feature 3}

**Usage**:
1. Save the file as `{app-name}.html`
2. Open in any browser
3. Works offline
4. Data auto-saves to your browser

**Customization**:
- Colors: Edit the CSS variables at the top
- Features: Modify the JavaScript section
- Layout: Adjust the HTML structure

Then provide the complete HTML file.

Common App Types

Dashboard

Purpose: Display metrics, status, and key information Elements: Cards, charts, progress bars, status indicators Data: Real-time or static metrics Example: Project status dashboard, analytics viewer

Tracker

Purpose: Record and monitor recurring items Elements: Add/​remove items, checkboxes, timestamps Data: List of items with status and dates Example: Habit tracker, task list, mood journal

Form/​Input

Purpose: Collect and validate user input Elements: Input fields, validation, submit button Data: Form submissions with timestamps Example: Survey, calculator, data entry tool

Visualization

Purpose: Display data visually Elements: Charts, graphs, timelines Data: Visual representation of datasets Example: Chart builder, timeline viewer, graph tool

Interactive Tool

Purpose: Perform specific tasks or calculations Elements: Controls, real-time updates, results Data: Temporary or persistent tool state Example: Timer, converter, game, simulator

Advanced Features

Dark/​Light Mode Toggle

function toggleTheme() {
  const currentTheme = document.body.dataset.theme || 'dark';
  const newTheme = currentTheme === 'dark' ? 'light' : 'dark';
  document.body.dataset.theme = newTheme;
  localStorage.setItem('theme-preference', newTheme);
}

// Load saved theme
document.body.dataset.theme = localStorage.getItem('theme-preference') || 'dark';

Export Data

function exportData() {
  const data = Storage.load();
  const blob = new Blob([JSON.stringify(data, null, 2)], { type: 'application/​json' });
  const url = URL.createObjectURL(blob);
  const a = document.createElement('a');
  a.href = url;
  a.download = `app-data-${Date.now()}.json`;
  a.click();
  URL.revokeObjectURL(url);
}

Import Data

function importData() {
  const input = document.createElement('input');
  input.type = 'file';
  input.accept = 'application/​json';
  input.onchange = (e) => {
    const file = e.target.files[0];
    const reader = new FileReader();
    reader.onload = (event) => {
      try {
        const data = JSON.parse(event.target.result);
        Storage.save(data);
        location.reload();
      } catch (error) {
        alert('Invalid file format');
      }
    };
    reader.readAsText(file);
  };
  input.click();
}

Browser Notifications

async function notifyUser(title, body) {
  if ('Notification' in window && Notification.permission === 'granted') {
    new Notification(title, { body });
  } else if (Notification.permission !== 'denied') {
    const permission = await Notification.requestPermission();
    if (permission === 'granted') {
      new Notification(title, { body });
    }
  }
}

Styling Guidelines

See styling.md for:

• Complete CSS framework
• Color schemes
• Responsive breakpoints
• Animation patterns
• Accessibility guidelines

Integration with Other Skills

Rapid Prototyper

If app needs backend:

browser-app-creator → Creates frontend
rapid-prototyper → Creates backend API
Result: Full-stack app

Context Manager

Save app decisions:

remember: Created habit tracker with localStorage
Type: PROCEDURE
Tags: browser-app, localStorage, tracking

Error Debugger

If app has bugs:

Automatically invokes error-debugger for:
- JavaScript errors
- localStorage issues
- Browser compatibility

Quality Checklist

Before delivering, verify:

• ✅ Single file (HTML + CSS + JS)
• ✅ Works offline (no external dependencies)
• ✅ Buttons ≥60px height
• ✅ Dark mode default
• ✅ localStorage auto-save
• ✅ Visual feedback on actions
• ✅ Mobile responsive
• ✅ No console errors
• ✅ Data persists on reload

Example Output

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Habit Tracker</​title>
  <style>
    /​* Complete styles here */
  </​style>
</​head>
<body>
  <h1>Habit Tracker</​h1>
  <div id="app">
    <!-- App UI here -->
  </​div>
  <script>
    // Complete logic here
  </​script>
</​body>
</​html>

Success Criteria

✅ App works immediately after opening ✅ Data persists across browser sessions ✅ ADHD-optimized (large buttons, auto-save) ✅ No setup or installation required ✅ Mobile-friendly ✅ Professional appearance ✅ Intuitive to use ✅ Handles errors gracefully

Additional Resources

• App Templates - Complete working examples
• Styling Guide - CSS patterns and color schemes

Quick Reference

Trigger Phrases

• "create app"
• "build tool"
• "make dashboard"
• "create tracker"
• "build calculator"
• "make timer"

File Location

All created apps should be saved to:

• Linux/​macOS: ~/​.claude-artifacts/
• Windows: %USERPROFILE%\.claude-artifacts\

Common Patterns