if 
(Win && Explorer && Version=="4")
{document.write('<LINK rel="stylesheet" type="text/css" href="/css/winie_style.css">');}

else if
(Win && Netscape && Version=="5")
{document.write('<LINK rel="stylesheet" type="text/css" href="/css/winns_style.css">');}

else if
(Win && Netscape && Version=="4")
{document.write('<LINK rel="stylesheet" type="text/css" href="/css/winns_style.css">');}

else if
(Explorer && Mac && Version=="4")
{document.write('<LINK rel="stylesheet" type="text/css" href="/css/macie_style.css">');}

else if
(Mac && Netscape && Version=="5")
{document.write('<LINK rel="stylesheet" type="text/css" href="/css/macns_style.css">');}

else if
(Mac && Netscape && Version=="4")
{document.write('<LINK rel="stylesheet" type="text/css" href="/css/macns_style.css">');}