js下获得客户端操作系统的函数代码(1:vista,2:windows7,3:2000,4:xp,5:2003,6:2008)

//获得客户端操作系统(1:vista,2:windows7,3:2000,4:xp,5:2003,6:2008) 
function GetOSInfo(){ 
var _pf = navigator.platform; 
var appVer = navigator.userAgent; 
if(_pf == "Win32" || _pf == "Windows") 
{ 
if(appVer.indexOf("WOW64")>-1){ 
_bit = "64位"; 
}else{ 
_bit = "32位"; 
} 
if(appVer.indexOf("Windows NT 6.0") > -1 || appVer.indexOf("Windows Vista") > -1) 
{ 
if(_bit=='64位' || appVer.indexOf("Windows Vista") > -1){ 
return 'Windows_vista '+_bit; 
}else{ 
return "Unknow1"; 
} 
}else if(appVer.indexOf("Windows NT 6.1") > -1 || appVer.indexOf("Windows 7") > -1) { 
if(_bit=='32位' || appVer.indexOf("Windows 7") > -1){ 
return 'Windows_7 '+_bit; 
}else{ 
return "Unknow"; 
} 
}else { 
try{ 
var _winName = Array('2000','XP','2003'); 
var _ntNum = appVer.match(/Windows NT 5.\d/i).toString(); 
return 'Windows_' + _winName[_ntNum.replace(/Windows NT 5.(\d)/i,"$1")]+" "+_bit; 
}catch(e){return 'Windows';} 
} 
}else if(_pf == "Mac68K" || _pf == "MacPPC" || _pf == "Macintosh") 
{ 
return "Mac"; 
}else if(_pf == "X11") 
{ 
return "Unix"; 
}else if(String(_pf).indexOf("Linux") > -1) 
{ 
return "Linux"; 
}else 
{ 
return "Unknow"; 
} 
}