for website performance

<filesMatch "\.(ico|pdf|flv|jpg|jpeg|png|gif|js|css|swf)$">

Header set Cache-Control "max-age=604800,public"

</filesMatch>

#################################

<IfModule mod_headers.c>

  <FilesMatch "\.(js|css|xml|gz)$">

    Header append Vary: Accept-Encoding

  </FilesMatch>

</IfModule>