In the past, performance was not considered one of the top priorities when developing web applications, but nowadays web app performance is most important for success, and Google also taking site speed into account in the search rankings.
So In order to get better rankings & to provide best user experience we should use suitable Cache mechanism to your app.
coming to the point, Leverage Browser Cache is the store(remember) the Resources in the Browser that has already loaded.so that if the visitor goes to the next page he/she no need to load the resources(CSS, js, images..etc) again.
Here is htaccess, add this to your htaccess file
if you are CodeIgniter Developer this post will help you to seep up your app Improve CodeIgniter App Speed?
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