caching static html css js images
# cache images/pdf docs for 1 week
<FilesMatch "\.(ico|pdf|jpg|jpeg|png|gif)$">
Header set Cache-Control "max-age=604800, public, must-revalidate"
Header unset Last-Modified
</FilesMatch>
# cache html/htm/xml/txt diles for 2 days
<FilesMatch "\.(css|js)$">
Header set Cache-Control "max-age=172800, must-revalidate"
</FilesMatch>