Creating a link from your DocBook document to a website is easy. You use the ulink element, putting the target URL in the ulink's url attribute. For example:

For more information on DocBook, go to the
<ulink  url="https://sourceforge.net/projects/docbook/">DocBook 
SourceForge website</ulink>
or to <ulink  url="http://docbook.org"/>.

The first ulink example is not empty, so its text content becomes the hot text in HTML output. The second ulink is empty, so the stylesheet will automatically copy its URL to use as the hot text.

In HTML output, you can have the target document appear in a separate window if you set the ulink.target parameter to a different window name. That adds a target attribute to the HTML anchor tag. By default, the parameter's value is _top, which loads the content into the topmost frame, which is likely the same window.

For FO output, you can choose whether the url attribute value for the ulink is printed. If you just set the parameter ulink.show to nonzero, then the URL appears in square brackets after the ulink text. If you also set the parameter ulink.footnotes to nonzero, then the URL becomes a footnote to the ulink text. Regardless of the parameter settings, if the URL exactly matches the ulink text string (or the ulink element is empty, which produces the same result), then the stylesheet does not repeat the same URL in brackets or a footnote.