A link, by default, opens in the same window or frame that contains the link. You can choose another target for each link individually, as described on page 108, or specify a default target for all the links on a page.
Figure 6.14. Use the base tag to set the default target (in this case the characters window) in order to save typing. Notice that I no longer have to specify the target for the links in the first paragraph. This document is equivalent to the one shown in Figure 6.11.
To set a default target for a page: