Expires and Cache-Control are “strong caching headers” Last-Modified and ETag are “weak caching headers” First the browser checks Expires/Cache-Control to determine whether or not to make a request to the servers. If it has to make a request, it will send Last-Modified/ETag in the HTTP request. If the Etag value of the document matches that, … Read more
Expires module in Apache solves this a2enmod expires it needs to be loaded in server config, and set up in .htaccess (or in server config). With an Expires header, the resource is only requested the first time. Before the expiration date, subsequent requests are fulfilled from browser cache. After the specified time expires and the … Read more
The behavior you are seeing is the intended (see RFC7234 for more details), specified behavior: All modern browsers will send HTTP requests to the server for every page element displayed, regardless of cache status. This was a design decision made at the request of web services (especially advertising networks) to ensure that HTTP servers were … Read more