var Win   = navigator.userAgent.indexOf("Win") != -1 ? true : false 
var Mac   = navigator.userAgent.indexOf("Mac") != -1 ? true : false 

if (navigator.appName=="Microsoft Internet Explorer") {

if (Win)     cssurl = "../../css/win_ie.css"
else if(Mac) cssurl = "../../css/mac_ie.css"

} else if (navigator.appName=="Netscape") {

if (Win)     cssurl = "../../css/win_nn.css"
else if(Mac) cssurl = "../../css/mac_nn.css"

} else {
if (Win)     cssurl = "../../css/win.css"
else if(Mac) cssurl = "../../css/mac.css"
}

document.write('<link rel="stylesheet" ')
document.write('      type="text/css"  ')
document.write('      href="'+cssurl+'"')
document.write('>')