🎯 Triple Nested Iframes - All Origin Combinations

📋 Scenario 1: Same Origin → Cross Origin → Cross Origin

🔄 Origin Flow:

Main Page (Same Origin) → Level 1 (Cross Origin) → Level 2 (Cross Origin)

This demonstrates a same-origin page embedding a cross-origin iframe, which then embeds another cross-origin iframe.

🔧 Technical Implementation:

Main page loads a same-origin HTML file
That file contains a cross-origin iframe (data URL)
The cross-origin iframe contains another cross-origin iframe (httpbin.org)
Each level has different security contexts

📋 Scenario 3: Triple Cross-Origin Nesting

🔄 Origin Flow:

Level 1 (Cross Origin) → Level 2 (Cross Origin) → Level 3 (Cross Origin)

This demonstrates three levels of cross-origin iframe nesting, each from different domains.

✅ This Works Because:

Each level is a separate cross-origin context
Data URLs create isolated security contexts
Final level loads real external content (httpbin.org)
Each iframe is sandboxed for security

📋 Scenario 4: Triple Same-Origin Nesting

🔄 Origin Flow:

Level 1 (Same Origin) → Level 2 (Same Origin) → Level 3 (Same Origin)

This demonstrates three levels of same-origin iframe nesting, all from the same domain.

✅ Same-Origin Benefits:

All frames can communicate freely
No cross-origin security restrictions
Parent can access child frame content
Shared cookies and local storage

🛡️ Security & Technical Summary

🔍 Key Observations:

✅ Same-Origin Iframes:

Full DOM access between frames
Shared security context
Can reference local files directly
No postMessage needed

❌ Cross-Origin Iframes:

Isolated security contexts
No direct DOM access
Must use postMessage API
Subject to CSP and X-Frame-Options

🔧 Implementation Notes:

Data URLs: Used to simulate cross-origin content reliably
Sandbox Attributes: Control iframe capabilities and security
Console Logging: Demonstrates access restrictions in developer tools
Fallback Content: Provides accessibility for unsupported browsers
Responsive Design: Adapts to different screen sizes