xxxxxxxxxx
RewriteEngine on
Options -MultiViews
# remove trailing / from the url
RewriteRule ^(.+)/$ /$1 [L,R=301]
# Remove .html (or htm) from visible URL (permanent redirect)
RewriteCond %{REQUEST_URI} ^/(.+)\.html?$ [nocase]
RewriteRule ^ /%1 [L,R=301]
# Quietly point back to the HTML file (temporary/undefined redirect):
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}.html -f
RewriteRule ^ %{REQUEST_URI}.html [END]