JavaScript Defer and Async vs Module Scripts

Developers should use defer and async to improve page load times and user experience, especially for scripts that are not critical for initial rendering meets developers should use module scripts when building complex web applications that require code splitting, dependency management, and encapsulation to avoid global namespace pollution. Here's our take.

JavaScript Defer and Async

Nice Pick

Developers should use defer and async to improve page load times and user experience, especially for scripts that are not critical for initial rendering

Pros

• Use 'defer' for scripts that depend on the DOM being fully loaded, such as interactive features, and 'async' for independent scripts like analytics or ads that don't rely on other elements
• Related to: javascript, html

Cons

• Specific tradeoffs depend on your use case

Module Scripts

Developers should use module scripts when building complex web applications that require code splitting, dependency management, and encapsulation to avoid global namespace pollution

Pros

• They are essential for leveraging modern JavaScript features like ES6 modules in browsers, enabling better tooling integration (e
• Related to: es6-modules, javascript

Cons

• Specific tradeoffs depend on your use case

The Verdict

Use JavaScript Defer and Async if: You want use 'defer' for scripts that depend on the dom being fully loaded, such as interactive features, and 'async' for independent scripts like analytics or ads that don't rely on other elements and can live with specific tradeoffs depend on your use case.

Use Module Scripts if: You prioritize they are essential for leveraging modern javascript features like es6 modules in browsers, enabling better tooling integration (e over what JavaScript Defer and Async offers.

The Bottom Line

JavaScript Defer and Async wins

Developers should use defer and async to improve page load times and user experience, especially for scripts that are not critical for initial rendering