Alternate HTML background-attachment Values

docbook-rng-5.0b4 xsl-1.72.0 oxygen-8.2.0 (eclipse-3.2.2
plugin)

 

Based on the html stylesheet transformed code fragment:

 

    background-repeat:
no-repeat;

    background-position: top left;

    /* The following properties make the watermark
"fixed" on the page. */

    /* I think that's just a bit too distracting for
the reader... */

    /* background-attachment: fixed; */

    /* background-position: center center; */

 

what are the alternate values for background-attachment?

 

Lastly, how does one extend/override the default stylesheet
to enable html/xhtml support of alternate background-attachment values?

 

Ray