If your web server is Apache you can use mod_rewrite to hide extensions of static .html files
To do that make sure that mod_rewrite is enabled (ask hosting support if you don’t know how to check it) and create .htaccess (starts with dot) file in the root of your site. Then put this into that file:
Use caution with mega’s code as, without the second RewriteCond, the EVERYTHING atom in the RewriteRule could redirect to http://example.com/.html. IMHO, better to use:
RewriteEngine on
RewriteCond %{REQUEST_FILENAME}.html -f
RewriteRule .? %{REQUEST_URI}.html [L]
Note that I did not make the test for “not a directory”, I did not need to escape the dot character in the second RewriteCond statement and I don’t care what the EVERYTHING atom captured because it was already contained in the {REQUEST_URI} variable.
More on mod_rewrite in a tutorial with abundant every day examples at http://dk.co.nz/seo.