crawl4ai/docs/md_v2/apps/c4a-script

C4A-Script Interactive Tutorial

A comprehensive web-based tutorial for learning and experimenting with C4A-Script - Crawl4AI's visual web automation language.

🚀 Quick Start

Prerequisites

• Python 3.7+
• Modern web browser (Chrome, Firefox, Safari, Edge)

Running the Tutorial

1. Clone and Navigate

   git clone https://github.com/unclecode/crawl4ai.git
   cd crawl4ai/docs/examples/c4a_script/tutorial/
   

2. Install Dependencies

   pip install -r requirements.txt
   

3. Launch the Server

   python server.py
   

4. Open in Browser

   http://localhost:8000
   

🌐 Try Online: Live Demo

2. Try Your First Script

# Basic interaction
GO playground/
WAIT `body` 2
IF (EXISTS `.cookie-banner`) THEN CLICK `.accept`
CLICK `#start-tutorial`

🎯 What You'll Learn

Core Features

• 📝 Text Editor: Write C4A-Script with syntax highlighting
• 🧩 Visual Editor: Build scripts using drag-and-drop Blockly interface
• 🎬 Recording Mode: Capture browser actions and auto-generate scripts
• ⚡ Live Execution: Run scripts in real-time with instant feedback
• 📊 Timeline View: Visualize and edit automation steps

📚 Tutorial Content

Basic Commands

• Navigation: GO url
• Waiting: WAIT selector timeout or WAIT seconds
• Clicking: CLICK selector
• Typing: TYPE "text"
• Scrolling: SCROLL DOWN/UP amount

Control Flow

• Conditionals: IF (condition) THEN action
• Loops: REPEAT (action, condition)
• Procedures: Define reusable command sequences

Advanced Features

• JavaScript evaluation: EVAL code
• Variables: SET name = "value"
• Complex selectors: CSS selectors in backticks

🎮 Interactive Playground Features

The tutorial includes a fully interactive web app with:

1. Authentication System

• Login form with validation
• Session management
• Protected content

2. Dynamic Content

• Infinite scroll products
• Pagination controls
• Load more buttons

3. Complex Forms

• Multi-step wizards
• Dynamic field visibility
• Form validation

4. Interactive Elements

• Tabs and accordions
• Modals and popups
• Expandable content

5. Data Tables

• Sortable columns
• Search functionality
• Export options

🛠️ Tutorial Features

Live Code Editor

• Syntax highlighting
• Real-time compilation
• Error messages with suggestions

JavaScript Output Viewer

• See generated JavaScript code
• Edit and test JS directly
• Understand the compilation

Visual Execution

• Step-by-step progress
• Element highlighting
• Console output

Example Scripts

Load pre-written examples demonstrating:

• Cookie banner handling
• Login workflows
• Infinite scroll automation
• Multi-step form completion
• Complex interaction sequences

📖 Tutorial Sections

1. Getting Started

Learn basic commands and syntax:

GO https://example.com
WAIT `.content` 5
CLICK `.button`

2. Handling Dynamic Content

Master waiting strategies and conditionals:

IF (EXISTS `.popup`) THEN CLICK `.close`
WAIT `.results` 10

3. Form Automation

Fill and submit forms:

CLICK `#email`
TYPE "user@example.com"
CLICK `button[type="submit"]`

4. Advanced Workflows

Build complex automation flows:

PROC login
  CLICK `#username`
  TYPE $username
  CLICK `#password`
  TYPE $password
  CLICK `#login-btn`
ENDPROC

SET username = "demo"
SET password = "pass123"
login

🎯 Practice Challenges

Challenge 1: Cookie & Popups

Handle the cookie banner and newsletter popup that appear on page load.

Challenge 2: Complete Login

Successfully log into the application using the demo credentials.

Challenge 3: Load All Products

Use infinite scroll to load all 100 products in the catalog.

Challenge 4: Multi-step Survey

Complete the entire multi-step survey form.

Challenge 5: Full Workflow

Create a script that logs in, browses products, and exports data.

💡 Tips & Tricks

1. Use Specific Selectors

# Good - specific
CLICK `button.submit-order`

# Bad - too generic
CLICK `button`

2. Always Handle Popups

# Check for common popups
IF (EXISTS `.cookie-banner`) THEN CLICK `.accept`
IF (EXISTS `.newsletter-modal`) THEN CLICK `.close`

3. Add Appropriate Waits

# Wait for elements before interacting
WAIT `.form` 5
CLICK `#submit`

4. Use Procedures for Reusability

PROC handle_popups
  IF (EXISTS `.popup`) THEN CLICK `.close`
  IF (EXISTS `.cookie-banner`) THEN CLICK `.accept`
ENDPROC

# Use anywhere
handle_popups

🔧 Troubleshooting

Common Issues

1. "Element not found"

   • Add a WAIT before clicking
   • Check selector specificity
   • Verify element exists with IF

2. "Timeout waiting for selector"

   • Increase timeout value
   • Check if element is dynamically loaded
   • Verify selector is correct

3. "Missing THEN keyword"

   • All IF statements need THEN
   • Format: IF (condition) THEN action

🚀 Using with Crawl4AI

Once you've mastered C4A-Script in the tutorial, use it with Crawl4AI:

from crawl4ai import AsyncWebCrawler, CrawlerRunConfig

config = CrawlerRunConfig(
    url="https://example.com",
    c4a_script="""
    WAIT `.content` 5
    IF (EXISTS `.load-more`) THEN CLICK `.load-more`
    WAIT `.new-content` 3
    """
)

async with AsyncWebCrawler() as crawler:
    result = await crawler.arun(config=config)

📝 Example Scripts

Check the scripts/ folder for complete examples:

• 01-basic-interaction.c4a - Getting started
• 02-login-flow.c4a - Authentication
• 03-infinite-scroll.c4a - Dynamic content
• 04-multi-step-form.c4a - Complex forms
• 05-complex-workflow.c4a - Full automation

🏗️ Developer Guide

Project Architecture

tutorial/
├── server.py              # Flask application server
├── assets/               # Tutorial-specific assets
│   ├── app.js            # Main application logic
│   ├── c4a-blocks.js     # Custom Blockly blocks
│   ├── c4a-generator.js  # Code generation
│   ├── blockly-manager.js # Blockly integration
│   └── styles.css        # Main styling
├── playground/           # Interactive demo environment
│   ├── index.html        # Demo web application
│   ├── app.js           # Demo app logic
│   └── styles.css       # Demo styling
├── scripts/             # Example C4A scripts
└── index.html           # Main tutorial interface

Key Components

1. TutorialApp (assets/app.js)

Main application controller managing:

• Code editor integration (CodeMirror)
• Script execution and browser preview
• Tutorial navigation and lessons
• State management and persistence

2. BlocklyManager (assets/blockly-manager.js)

Visual programming interface:

• Custom C4A-Script block definitions
• Bidirectional sync between visual blocks and text
• Real-time code generation
• Dark theme integration

3. Recording System

Powers the recording functionality:

• Browser event capture
• Smart event grouping and filtering
• Automatic C4A-Script generation
• Timeline visualization

Customization

Adding New Commands

1. Define Block (assets/c4a-blocks.js)
2. Add Generator (assets/c4a-generator.js)
3. Update Parser (assets/blockly-manager.js)

Themes and Styling

• Main styles: assets/styles.css
• Theme variables: CSS custom properties
• Dark mode: Auto-applied based on system preference

Configuration

# server.py configuration
PORT = 8000
DEBUG = True
THREADED = True

API Endpoints

• GET / - Main tutorial interface
• GET /playground/ - Interactive demo environment
• POST /execute - Script execution endpoint
• GET /examples/<script> - Load example scripts

🔧 Troubleshooting

Common Issues

Port Already in Use

# Kill existing process
lsof -ti:8000 | xargs kill -9
# Or use different port
python server.py --port 8001

Blockly Not Loading

• Check browser console for JavaScript errors
• Verify all static files are served correctly
• Ensure proper script loading order

Recording Issues

• Verify iframe permissions
• Check cross-origin communication
• Ensure event listeners are attached

Debug Mode

Enable detailed logging by setting DEBUG = True in assets/app.js

📚 Additional Resources

• C4A-Script Documentation - Complete language guide
• API Reference - Detailed command documentation
• Live Demo - Try without installation
• Example Scripts - More automation examples

🤝 Contributing

Bug Reports

1. Check existing issues on GitHub
2. Provide minimal reproduction steps
3. Include browser and system information
4. Add relevant console logs

Feature Requests

1. Fork the repository
2. Create feature branch: git checkout -b feature/my-feature
3. Test thoroughly with different browsers
4. Update documentation
5. Submit pull request

Code Style

• Use consistent indentation (2 spaces for JS, 4 for Python)
• Add comments for complex logic
• Follow existing naming conventions
• Test with multiple browsers

---

Happy Automating! 🎉

Need help? Check our documentation or open an issue on GitHub.