var strBrowseren = navigator.appVersion 
if ( strBrowseren.indexOf("Mac") > -1 ){ 
        document.write('<LINK REL="StyleSheet" HREF="style.css" TYPE="text/css">') 
} else { 
        if ( navigator.appName.indexOf("Netscape") > -1 ){ 
                document.write('<LINK REL="StyleSheet" HREF="style.css" TYPE="text/css">') 
        } else { 
                document.write('<LINK REL="StyleSheet" HREF="style-ie.css" TYPE="text/css">') 
        } 
}