Description

The base element, which is contained in the head of the document, provides a method for defining the base URL for all links and form submissions on a page. It also provides a common target (in the form of a named window) for all of these links or form submissions.

This element isn’t used very often these days, as making links is usually a simple case of creating links to documents relative to the web server root, like so:

I've published my <a href="/travel-writing/">holiday diaries</a>,
    including the <a href="/travel-writing/prague/2006/day2.html">crazy
    bone church at Kutna Hora</a>

When the links are accessed, the server will look for the document’s reference in the domain root, regardless of the location of the page that contains these links. It doesn’t matter one iota whether the referencing page is in the web server’s document root folder, or ten directory levels down—the server still looks in the root because the links begin with a "/" character.