I put only index.html in /var/www/html.
The page doesn't update after I changed the contents of index.html and reload.
I already disable cache_module in httpd.conf like this below.
# LoadModule cache_module modules/mod_cache.so
# LoadModule disk_cache_module modules/mod_disk_cache.so
if you are using htaccess then you can do like
#Initialize mod_rewrite
RewriteEngine On
<FilesMatch "\.(html|htm|js|css)$">
FileETag None
<IfModule mod_headers.c>
Header unset ETag
Header set Cache-Control "max-age=0, no-cache, no-store, must-revalidate"
Header set Pragma "no-cache"
Header set Expires "Wed, 12 Jan 1980 05:00:00 GMT"
</IfModule>
</FilesMatch>