What are some effective browser caching techniques?

What are some effective browser caching techniques?

Browser caching techniques help improve website performance by storing resources locally. Some effective techniques include:

1. Cache-Control Headers: Specify how long browsers should cache files.
2. ETags: Use entity tags to validate cached resources.
3. Expires Headers: Set expiration dates for cached content.
4. Service Workers: Implement service workers for advanced caching strategies.
5. Versioning: Change file names or query strings when updating resources.

How do Cache-Control headers work?

Cache-Control headers dictate how, and for how long, browsers and intermediate caches should store resources. For example, Cache-Control: max-age=3600 tells the browser to cache the resource for one hour.

What is the difference between Cache-Control and Expires headers?

The Cache-Control header is more flexible and allows for directives like max-age, while the Expires header specifies an exact date and time when the cached resource should be considered stale. Cache-Control is preferred in modern applications.

Can you explain how ETags work?

ETags, or entity tags, are unique identifiers assigned to a specific version of a resource. When a browser requests a resource, it sends the ETag it has. If the resource hasn't changed, the server responds with a 304 Not Modified status, saving bandwidth.