Identify whether the operating system is Vista's JS Code

How can I use ASP to identify that the operating system is Vista? I found a function on the Internet, but it cannot be determined that it is a Vista system. I hope you can help me.
This is the function I found online:
Function getcurros ()
Dim info
Info = navigator. appversion
If instr (Info, "nt 5.1")> 0 then
Getcurros = "Windows XP"
Elseif instr (Info, "tel")> 0 then
Getcurros = "telport"
Elseif instr (Info, "webzip")> 0 then
Getcurros = "webzip"
Elseif instr (Info, "flashget")> 0 then
Getcurros = "flashget"
Elseif instr (Info, "offline")> 0 then
Getcurros = "offline"
Elseif instr (Info, "nt 5")> 0 then
Getcurros = "Window 2000"
Elseif instr (Info, "NT 4")> 0 then
Getcurros = "Windows NT4"
Elseif instr (Info, "98")> 0 then
Getcurros = "Windows 98"
Elseif instr (Info, "95")> 0 then
Getcurros = "Windows 95"
Else
Getcurros = "unknow"
End if
End Function
If you still have better functions, I 'd like to thank you first. <textarea id="runcode29941"></textarea> Xmlns = "http://www.w3.org/1999/xhtml">