var Win=(navigator.userAgent.indexOf("Win")!=-1);
var Mac=(navigator.userAgent.indexOf("Mac")!=-1);
var Explorer=(navigator.appName.indexOf("Explorer")!=-1);
var Netscape=(navigator.userAgent.indexOf("Netscape")!=-1);
var Firefox=(navigator.userAgent.indexOf("Firefox")!=-1);
var Safari=(navigator.userAgent.indexOf("Safari")!=-1);
var opera=(navigator.userAgent.indexOf("Opera")!=-1);
var Version=navigator.appVersion.charAt(0);
var Version2=navigator.appVersion;
var appVer01=Version2.indexOf("MSIE",0)+5;
var appVer02=Version2.indexOf(".",appVer01);
var appVer00=Version2.substring(appVer01,appVer02);

if
(Win && Explorer && appVer00=="6")
{document.write("<LINK rel='stylesheet' href='"+level+"css/win_ie.css' type='text/css'>");}
else if
(Win && Explorer && appVer00=="7")
{document.write("<LINK rel='stylesheet' href='"+level+"css/win_ie.css' type='text/css'>");}
else if
(Win)
{document.write("<LINK rel='stylesheet' href='"+level+"css/other.css' type='text/css'>");}
else if
(Mac)
{document.write("<LINK rel='stylesheet' href='"+level+"css/mac.css' type='text/css'>");}