JScript to detect if Windows user admin

I need JScript that will be launched on Windows from command line. The script shoudl detect (using WScript, I guess) is the current user local admin on given computer or no.

How could I do this?

Code:

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var objNetwork=new ActiveXObject("WScript.Network");
var objAdmins = GetObject("WinNT://"+objNetwork.ComputerName+"/Administrators");
var colMembers = objAdmins.Members();
var Admin=false;
for (var enumItems=new Enumerator(colMembers); !enumItems.atEnd(); enumItems.moveNext()) {
        var objMember=enumItems.item();
        if (objNetwork.UserName.toLowerCase()==objMember.Name.toLowerCase()) Admin=true;
}
(Admin==true) ? WScript.Echo("Yes, you are a local admin") : WScript.Echo("Tough luck, you're no admin");

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Code:

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var net = WScript.CreateObject("WScript.Network");
var shell = WScript.CreateObject("WScript.Shell");

var exec = shell.Exec("net localgroup administrators");
var result = exec.StdOut.ReadAll();
WScript.Echo("admin: "+(result.indexOf("\n"+net.UserName+"\r")!=-1));

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net localgroup administrators | find "%USERNAME%" fails somehow... =S If not would be 3 lines only script...