Supposing I\'m setting a background image for a web page in CSS like this:
body {
font-size: 62.5%; /* Resets 1em to 10px */
font-family: Verdana, Arial, Sans
Nowadays this can be done in all the "modern" browsers (not < IE9, afaik). I can confirm that it works in Firefox, Opera, Chrome. There is no reason not to do it, as long as you have a decent fallback solution for older browsers / IE.
For the syntax you can choose between
background:url(..) repeat-x left top, url(..) repeat-x left bottom;
and
background-image:url(..), url(..); background-position:left top, left bottom; background-repeat:repeat-x;
You don't need the linebreaks, but the comma is important.
Attention! The following will create two backgrounds, even though you specified only one image url:
background-image:url(..); background-position:top, bottom;
And of course, there is the alternative to use nested containers, but this will bloat your html.