help for framespacing attribute

Hello,
In xhtml 1.0 the framespacing attribute is not allowed anymore with <frameset>.
But when I create a frameset without this attribute, i have a space beetween my
frames also if i put frameborder="0" in the frame element.

I used too a css for fix margin:        margin:0; padding:0; 
border-width:0; border-style:none;

Why can reduce space between frames if framespacing isn´t allowed in XHTML?

(sorry for my bad english?