HTML and CSS Reference
files, to cache each of these files for at least a year since the first time it was ac-
cessed, unless the user deliberately clears their cache.
Yahoo's best practices for speeding up your site has a detailed explanation
of what the Expires header does at developer.yahoo.com/performance/
Custom 404 page
HTML5 Boilerplate provides a custom 404 page called 404.html . But, this will nev-
er be used, unless the server knows to serve this file every time a resource is not
found. HTML5 Boilerplate's .htaccess file has a configuration that tells the server
to use this file as follows:
ErrorDocument 404 /404.html
Make sure to refer to the 404.html using the full path. For example, on a Mac, the
full path would be /~<username>/404.html , if you are hosting it in the website's
folder under your <username> folder.
The following screenshot shows how a browser renders the default HTML5 Boiler-
plate 404 page, when HTML5 Boilerplate's .htaccess file is used: