Configuring the MIME type will depend on what server you're using. (Note that the type='text/cache-manifest'
you have on the <html>
tag doesn't do anything.) If you're using Apache, you should be able to add
AddType text/cache-manifest .appcache
to either the .htaccess
file or to your server configuration (httpd.conf
, apache.conf
, or something else). See here. Similar configuration documentation should be available if you're using a different web server.