white space handling

Hello,

I've tried to find something on white space handling in html/xhtml (Just as
it is described for SVG), but I can't find anything useful.

I read somewhere that one should use:

<span>Test <span>something</span></span>

instead of

<span>Test<span> something</span></span>

But where are the rules for this described in either the xml or html spec?

thanks,

--
Sigurd Lerstad