Thus, the set of access key assignments is small. The reason is that this avoids clashes with the built-in assignments in different browsers. - The rest of this page just briefly explains what access keys are, in general.
Access keys are keyboard shortcuts for accessing links and form fields on Web pages. A page author can specify access key assignments for his pages. The assignments apply to one page only, but an author could, and naturally should, use some consistent approach through his site.
It depends on the browser whether and how access keys are supported. For example, Internet Explorer (version 4 or newer) on Windows supports them as follows: if you keep the Alt key depressed when hitting a normal key, you move a location on the page as assigned to the character in that normal key in access key assignments. For example, with the assignments listed above, Alt 1 then takes you to a link that points to the main page of the site. On some other browsers, such as Netscape 6, using an access key causes immediate transfer to the destination of the link.
More information, especially from an authoring viewpoint,
is available in the document
Improving accessibility with
accesskey in HTML forms and links.