object.GetTempName ( ) 

var fso, tempfile;
fso = new ActiveXObject("Scripting.FileSystemObject");

function CreateTempFile()
{
   var tfolder, tfile, tname, fname, TemporaryFolder = 2;
   tfolder = fso.GetSpecialFolder(TemporaryFolder);
   tname = fso.GetTempName();
   tfile = tfolder.CreateTextFile(tname);
   return(tfile);
}
tempfile = CreateTempFile();
tempfile.writeline("Hello World");
tempfile.close();

Dim fso, tempfile
Set fso = CreateObject("Scripting.FileSystemObject")

Function CreateTempFile 
   Dim tfolder, tname, tfile
   Const TemporaryFolder = 2
   Set tfolder = fso.GetSpecialFolder(TemporaryFolder)
   tname = fso.GetTempName    
   Set tfile = tfolder.CreateTextFile(tname)
   Set CreateTempFile = tfile
End Function

Set tempfile = CreateTempFile
tempfile.WriteLine "Hello World"
tempfile.Close