positioning depending on browser

[liunx]

I use the folding menu tree and somehow the positioning of the 2nd menu level is different in IE and NS. In IE it all looks ok, but in NS it's way off. Check it out:

<!-- w --><a class="postlink" href="http://www.panglipur.com/test/testtest.htm">www.panglipur.com/test/testtest.htm</a><!-- w -->

Is it possible to write a script that detects which browser is being used and in case of NS use a different stylesheet, see this part of the code:

#foldheaderX {
MARGIN-LEFT: -17px; LIST-STYLE-IMAGE: url(blok.gif); cursorointer;cursor:hand}
#foldheader {
MARGIN-LEFT: -17px; LIST-STYLE-IMAGE: url(blok_plus.gif); cursorointer;cursor:hand}
#foldinglist {
MARGIN-LEFT: 0px; LIST-STYLE-IMAGE: url(spacer.gif); cursorointer;cursor:hand}