var bIsWin = (navigator.appVersion.indexOf ("Win") != -1);
var bIsMac = (navigator.appVersion.indexOf ("Mac") != -1);
var bIsIE = (navigator.appName.indexOf ("Explorer") != -1);
var bIsWinIE = (bIsWin && bIsIE);
var bIsMacIE = (bIsMac && bIsIE);

if(bIsWinIE){ document.write ( '<link rel="stylesheet" type="text/css" href="' + jsdir + 'common/css/win_ie.css">' ); }
if(bIsMacIE){ document.write ( '<link rel="stylesheet" type="text/css" href="' + jsdir + 'common/css/mac_ie.css">' ); }