Clean • Professional
As JavaScript evolved through ECMAScript versions (ES6/ES2015 onwards), browser support has varied significantly. Microsoft’s Internet Explorer (IE) has historically lagged behind, while Microsoft Edge has progressively aligned with modern standards. Understanding compatibility is critical for developers maintaining legacy applications or targeting enterprise environments.
Last Major Version: IE11 (2013)
JavaScript Engine: Chakra (pre-EdgeHTML), primarily ES5 with limited ES6 support.
Status: Fully deprecated for general use as of June 15, 2022. Extended security updates continue for enterprise users until 2029.
Market Share: ~0.5% globally (mostly legacy enterprise systems).
Key Limitations for ES6+ Features:
let / const → Not supported, Babel transpilation required.Error Handling: Only basic try-catch-finally and throw work natively. Modern async error handling via Promises or async/await is unsupported without polyfills.
Enterprise Workarounds:
Legacy Edge (EdgeHTML, 2015–2019):
Chromium-based Edge (2020+):
Advantages: Modern Edge eliminates most cross-browser compatibility issues, enabling full use of ES6+ features and advanced error-handling mechanisms.
| Feature | Description | IE11 | Legacy Edge | Chromium Edge |
|---|---|---|---|---|
let / const | Block-scoped variables | None | Partial | Full |
| Arrow Functions | Concise function syntax | None | Partial | Full |
| Classes / Custom Errors | ES6 class syntax for inheritance and custom errors | None | Partial | Full |
| Promises | Async error handling with .catch() | Polyfill | Full | Full |
| async/await | Synchronous-like async code | Polyfill via transpile | Full | Full |
| Optional Chaining (?.) | Safe property access | None | None | Full |
| Error.cause | Nested error tracking | None | None | Full |
| Promise.finally | Cleanup after async operations | Polyfill | Partial | Full |
Sources: MDN, CanIUse, Microsoft Docs, Stack Overflow, LambdaTest.
Microsoft has officially ended support for Internet Explorer, gradually phasing it out across services:
Earlier Announcements:
Legacy Use Cases:
Solution: Microsoft Edge IE Mode allows running legacy web apps in a modern browser while maintaining compatibility.