11 March 2019
If Set the Last-Modified date to the last time the resource was changed. If the Last-Modified date is sufficiently far enough in the past, chances are the browser won’t refetch it and Specify a cache validator even with below coding in .htaccess.
There are use to page speed optimization.
<IfModule mod_headers.c> <FilesMatch "\.(bmp|css|flv|gif|ico|jpg|jpeg|js|pdf|png|svg|swf|tif|tiff)$"> Header set Last-Modified "Mon, 31 Aug 2009 00:00:00 GMT" </FilesMatch> </IfModule>